CN102245793B

CN102245793B - Constituent member of bearing, process for production of same, and ball-and-roller bearing provided with the constituent member

Info

Publication number: CN102245793B
Application number: CN200980150135.3A
Authority: CN
Inventors: 木泽克彦; 三上刚; 尾野健太郎; 中岛力
Original assignee: JTEKT Corp
Current assignee: JTEKT Corp
Priority date: 2008-12-12
Filing date: 2009-12-11
Publication date: 2014-07-09
Anticipated expiration: 2029-12-11
Also published as: EP2386669A1; US20110243488A1; EP2386669A4; EP2386669B1; CN102245793A; US8596875B2; EP3301201A1; WO2010067872A1

Abstract

The present invention provides a constituent member of a bearing, which can prolong the life of a ball-and-roller bearing and can ensure sufficient static load carrying capacity and dimensional stability; a process for production of the constituent member; and a ball-and-roller bearing which has a long life and exhibits sufficient static load carrying capacity and dimensional stability. A workpiece obtained by shaping a steel containing 3.2 to 5.0 mass% of Cr and 0.05 to less than 0.5 mass% of V is subjected to heat treatment such as carbonitriding, whereby a constituent member of a ball-and-roller bearing is produced. In the constituent member thus produced, the contents of C and N in the surface layer extending from the surface of the member to a depth of 10[mu]m fall within the ranges of 1.1-1.6 mass% and 0.1-1.0 mass% respectively; the Vickers hardness at a depth of 50[mu]m from the surface falls within the range of 740 to 900 (62-67 in terms of Rockwell C hardness); the content of gamma-iron at a depth of 10[mu]m from the surface falls with the range of 20-55 vol%; vanadium nitride particles having particle diameters of 0.2-2[mu]m and/or vanadium carbonitride particles having particle diameters of 0.2-2[mu]m are made present in the surface layer extending from the surface to a depth of 10[mu]m; and the area fraction of the particles in the surface layer extending from the surface to a depth of 10[mu]m falls within the range of 1-10%.

Description

Bearing component parts and manufacture method thereof and possess the rolling bearing of above-mentioned bearing component parts

Technical field

The present invention relates to bearing component parts and manufacture method thereof and possess the rolling bearing of above-mentioned bearing component parts.

Background technology

Rolling bearing bears in use in the situation of excessive static load and while rotation under the utmost point slow speed of revolution and bears larger shock load, and each roller surface of inner ring and the contact part of rolling body outside, tends to produce local tension set.This tension set increases along with the increase of load, in the time exceeding critical load (quiet specified rated load), will hinder smooth and easy rotation.For example, the in the situation that of spot contact bearing, the maximum contact stress between rolling body and the groove portion of outer inner ring is 4200Mpa left and right, in the time of the design of spot contact bearing, consider this stress, determines quiet specified rated load.

The raising of this quiet specified rated load forms one of problem into important for the miniaturization and of realizing rolling bearing.

On the other hand, when rolling bearing rotates at carry load, outside can load repeated stress on each roller surface of inner ring and the rolling surface of rolling body.Therefore, in the time of the continuous use certain period, will in the material of bearing component parts that forms rolling bearing, produce rolling contact fatigue, on roller surface and rolling surface, surfacial spalling occur.Until there is total revolution (being called " rolling fatigue life ") of the rolling bearing of the surfacial spalling of this roller surface and rolling surface as the replacing index of rolling bearing, this rolling fatigue life is longer, more can reduce the frequency of changing rolling bearing.

As the rolling bearing that has improved rolling fatigue life, learn the rolling bearing that possesses following Internal and external cycle, for example, to the high-carbon-chromium bearing steel such as JIS SUJ2 be implemented to mechanical workout etc. and be formed as the starting material of regulation shape, being implemented in carbon potential is in more than 1.2 carburizing atmospheres, at 840～870 ℃, to heat more than 3 hours carburizing treatment, then carry out chilling, and further implement temper, thus whole carbon amounts of the skin section of the scope till the degree of depth working are made to 1.0～1.6 quality % from surface to the maximum shear stress, and the solid solution carbon amount in the matrix of the skin section apart from the dark scope of surperficial 0.5mm is made to 0.6～1.0 quality %, make Carbide Precipitation in skin section, the amount of separated out carbide is made with area occupation ratio and counted 5～15%, the particle diameter of above-mentioned carbide particle is made to 3 μ m following (with reference to patent documentation 1).

But the purposes under the environment for use that from realizing the viewpoint of part miniaturization, the load that is additional to outer inner ring and rolling body increases, the high temperature of use temperature etc. is harsh is more and more, is seeking further high performance.

In addition, when rolling bearing uses under for example impurity is sneaked into condition, impurity can be pressed into as the Internal and external cycle of bearing component parts and rolling body, tends to form impression on the roller surface of Internal and external cycle and the surface of rolling body.The surface damage portions such as the impression being generated by this impurity become the starting point of the Fatigue peelback that stress concentration causes, and become one of the reason in the life-span of reducing rolling bearing.

Therefore, wish realize impurity sneak into the inferior rolling bearing of condition life-span improve.

In order to improve the life-span of rolling bearing, following scheme has been proposed, that is, the moulding starting material that formed regulation shape by the steel that form as the SUJ2 of bearing steel are implemented to carbonitriding processing, obtain thus bearing component parts.

In addition, following scheme has been proposed, for example, by the chromium by containing the above and less than 5.0 quality % of 3.2 quality %, the molybdenum of less than 1.0 quality %, the steel of the vanadium of less than 0.5 quality % etc. are formed as the moulding starting material of regulation shape, in the carburizing atmosphere that is 1.2～1.5 at carbon potential, be heated to 850～930 ℃, then carry out chilling, thus above-mentioned moulding starting material are implemented to carburizing treatment, subsequently, by tempering, the median size of the particle being made up of carbide of the skin section of the bearing component parts of rolling bearing is made below 0.5 μ m, the area occupation ratio of the particle being made up of above-mentioned carbide is made to 9～30%, more than Rockwell C hardness is made to 63 (Vickers' hardnesses 770), the remained austenite content of skin section is made to 30～50 volume % (with reference to patent documentation 2).

Patent documentation 1: TOHKEMY 2004-52101 communique

Patent documentation 2: TOHKEMY 2006-176863 communique

Summary of the invention

But, use the steel that formed by above-mentioned SUJ2 and the bearing component parts obtaining, because inner remained austenite content increases, therefore residual austenite cognition becomes martensite ageingly, along with volumetric expansion, easily produce dimensional change, there is the low this shortcoming of ageing dimensional stability.

In addition, the bearing component parts that above-mentioned patent documentation 2 is recorded, because the remained austenite content of skin section increases, therefore can realize the long lifetime of rolling bearing, but due to the corresponding minimizing of martensite volume in this bearing component parts, therefore there is yielding stress low and can not guarantee this shortcoming of sufficient static load ability.

Therefore, possesses the rolling bearing of the bearing component parts that above-mentioned patent documentation 2 records, although life, bear larger shock load but bear in use in the situation of excessive static load and while rotation under the utmost point slow speed of revolution, produce tension set at each roller surface of Internal and external cycle and the contact part branch of rolling body, in the time that above-mentioned static load or shock load exceed critical load, will hinder smooth and easy rotation.

And, the bearing component parts that above-mentioned patent documentation 2 is recorded, the bearing component parts obtaining is same with using the steel that are made up of above-mentioned SUJ2, and inner remained austenite content increases, and therefore has the low this shortcoming of ageing dimensional stability.

The present invention develops in light of this situation, and its object is, provides a kind of and can realize the long lifetime of rolling bearing and can guarantee sufficient static load ability and bearing component parts and the manufacture method thereof of sufficient dimensional stability.In addition, the object of the invention is to, a kind of long lifetime is provided and shows sufficient static load ability and the rolling bearing of sufficient dimensional stability.

Bearing component parts of the present invention, by the chromium that contains 3.2～5.0 quality %, the steel of the vanadium of the above and less than 0.5 quality % of 0.05 quality % obtain, there is the surface of having carried out fine grinding processing, it is characterized by, carbon content the upper layer of the scope from described surface to 10 μ m is 1.1～1.6 quality %, Vickers' hardness apart from the dark position of described surperficial 50 μ m is 740～900 (Rockwell C hardness is 62～67), remained austenite content apart from the dark position of described surperficial 10 μ m is 20～55 volume %, nitrogen content the upper layer of the scope from described surface to 10 μ m is 0.1～1.0 quality %, the particle of particle diameter 0.2～2 μ m that there is the particle of particle diameter 0.2～2 μ m being formed by vanadium nitride and/or formed by vanadium carbonitride the upper layer of the scope from described surface to 10 μ m, and, the area occupation ratio of the particle of the particle of particle diameter 0.2～2 μ m being made up of described vanadium nitride the upper layer of the scope from described surface to 10 μ m and/or particle diameter 0.2～2 μ m being made up of vanadium carbonitride is 1～10% (also referred to as " bearing component parts 1 ").In addition, so-called from surface to the upper layer of the scope of 10 μ m, be defined as surface and apart from the scope between the dark position of surperficial 10 μ m.

According to the bearing component parts 1 of formation described above, because the Vickers' hardness of the dark position of the surperficial 50 μ m of distance is 740～900 (Rockwell C hardness is 62～67), and the remained austenite content apart from the dark position of surperficial 10 μ m is 20～55 volume %, therefore can relax to the stress concentration of the surface damage portions such as described impression.And, described bearing component parts 1 is because the area occupation ratio of the particle of the particle of the particle diameter being made up of vanadium nitride 0.2～2 μ m the upper layer of the scope from surface to 10 μ m and/or particle diameter 0.2～2 μ m that is made up of vanadium carbonitride is 1～10%, even if therefore do not reduce remained austenite content, also can obtain higher yielding stress.

Therefore, according to bearing component parts 1 of the present invention, by the mitigation of the stress concentration to surface damage portions such as described impressions, can guarantee the long lifetime of rolling bearing, and, by higher yielding stress, can guarantee sufficient static load ability.

Described optimum selection of steels is the vanadium of the above and less than 0.5 quality % of silicon, the manganese of 0.05～0.7 quality %, the chromium of 3.2～5.0 quality %, the molybdenum of 0.1～1.0 quality %, the 0.05 quality % of the carbon that contains 0.7～0.9 quality %, 0.05～0.70 quality %, and remainder is iron and the inevitable steel of impurity.

In this case, the amount of the thick eutectic carbides of separating out when the steel processed of bearing component parts reduces, and the fatigure failure of bearing is suppressed, and after quenching, after carbonitriding and tempering, is guaranteed sufficient hardness.

In bearing component parts of the present invention, described bearing component parts is the raceway member with the groove portion of having carried out fine grinding processing, wherein preferred, the carbon that described steel contain 0.7～0.9 quality %; The carbon content being present in the upper layer of the scope from surface to 10 μ m of the non-grind section of the part beyond described groove portion is preferably 0.7～1.0 quality %, and, be 700～800 (also referred to as " bearing component parts 2 ") apart from the Vickers' hardness of the dark position of this surface 50 μ m.

In this case, because the surface from non-grind section that is present in the part beyond described groove portion is 0.7～1.0 quality % to the carbon content the upper layer of the scope of 10 μ m, and the Vickers' hardness apart from the dark position of this surface 50 μ m is 700～800, therefore, can suppress the generation of the over cargurization tissue of non-grind section.

Therefore, the bearing component parts 2 that possesses this formation can obtain the action effect of described bearing component parts 1, in addition, also easily bear from outside load, for example, if as the outer ring of rolling bearing, can improve the rolling fatigue life of this rolling bearing, and can give sufficient intensity to this rolling bearing.

The manufacture method of bearing component parts of the present invention is the manufacture method of described bearing component parts 1 therein on the one hand, it is characterized by, and comprising:

Manufacturing procedure, the steel of the vanadium of the chromium that contains 3.2～5.0 quality %, 0.05 quality % is above and less than 0.5 quality % are processed into regulation shape, obtain moulding starting material;

Carbonitriding treatment process, described moulding starting material are implemented carbonitriding processing and obtained intermediate raw material, it is in the carbonitriding atmosphere of 2～5 volume % that described carbonitriding is treated at carbon potential 0.9～1.3, ammonia concentration, these moulding starting material is heated at 850～900 ℃ to the processing of then carrying out chilling;

Temper operation, to described carbonitriding intermediate raw material after treatment, implements the temper that this intermediate raw material is heated more than 160 ℃; And

Finishing step, implement precision work by the intermediate raw material to after described temper and obtain following bearing component parts: in described bearing component parts, carbon content the upper layer of the scope from surface to 10 μ m is 1.1～1.6 quality %, Vickers' hardness apart from the dark position of surperficial 50 μ m is 740～900 (Rockwell C hardness is 62～67), remained austenite content apart from the dark position of surperficial 10 μ m is 20～55 volume %, nitrogen content the upper layer of the scope from surface to 10 μ m is 0.1～1.0 quality %, the particle of particle diameter 0.2～2 μ m that there is the particle of particle diameter 0.2～2 μ m being formed by vanadium nitride and/or formed by vanadium carbonitride the upper layer of the scope from surface to 10 μ m, and, the area occupation ratio of the particle of the particle of particle diameter 0.2～2 μ m being made up of described vanadium nitride the upper layer of the scope from surface to 10 μ m and/or particle diameter 0.2～2 μ m being made up of vanadium carbonitride is 1～10% (also referred to as " manufacture method 1 ").

In the manufacture method 1 of this formation of employing, to the chromium by containing 3.2～5.0 quality %, the moulding starting material that the steel of the vanadium of the above and less than 0.5 quality % of 0.05 quality % obtain, be implemented in carbon potential 0.9～1.3, ammonia concentration is these moulding starting material to be heated at 850～900 ℃ to the carbonitriding processing of then carrying out chilling in the carbonitriding atmosphere of 2～5 volume %, and, to carbonitriding intermediate raw material after treatment, implement the temper that this intermediate raw material is heated more than 160 ℃, therefore can make gained to the upper layer of the scope from surface to 10 μ m of bearing component parts carbon content be 1.1～1.6 quality %, Vickers' hardness apart from the dark position of surperficial 50 μ m is 740～900 (Rockwell C hardness is 62～67), making the remained austenite content of the position dark apart from surperficial 10 μ m is 20～55 volume %, making the nitrogen content the upper layer of the scope from surface to 10 μ m is 0.1～1.0 quality %, the particle of particle diameter 0.2～2 μ m that has the particle of particle diameter 0.2～2 μ m being formed by vanadium nitride and/or formed by vanadium carbonitride the upper layer of the scope from surface to 10 μ m, and, the area occupation ratio of the particle of particle diameter 0.2～2 μ m that makes the particle of particle diameter 0.2～2 μ m being made up of described vanadium nitride the upper layer of the scope from surface to 10 μ m and/or be made up of vanadium carbonitride is 1～10%.Therefore, according to manufacture method 1, the bearing component parts 1 of action effect that can accomplished above-mentioned excellence.

In addition, the manufacture method of bearing component parts of the present invention is the manufacture method of described bearing component parts 2 on the other hand, it is characterized by, and comprising:

Manufacturing procedure, the steel of the vanadium of the chromium of the carbon that contains 0.7～0.9 quality %, 3.2～5.0 quality %, 0.05 quality % is above and less than 0.5 quality % are processed into regulation shape, obtain at least having in the part that forms roller surface the moulding starting material of the raceway member of grind;

Heat treatment step, to described moulding starting material, the thermal treatment that enforcement comprises carbonitriding processing and obtain intermediate raw material, described carbonitriding is treated in carbon potential 0.9～1.3, ammonia concentration are the carbonitriding atmosphere of 2～5 volume % heats more than 4 hours processing by these moulding starting material at 850～900 ℃;

Finishing step, the part of the described roller surface of formation by the intermediate raw material to after described thermal treatment is implemented fine grinding processing, form described groove portion, obtain following raceway member: in described raceway member, be more than 1.1 quality % and less than 1.6 quality % from the surface of described groove portion to the carbon content the upper layer of the scope of 10 μ m, Vickers' hardness apart from the dark position of this surface 50 μ m is 740～900, remained austenite content apart from the dark position of described surperficial 10 μ m is 20～55 volume %, nitrogen content the upper layer of the scope from described surface to 10 μ m is 0.1～1.0 quality %, the particle of particle diameter 0.2～2 μ m that there is the particle of particle diameter 0.2～2 μ m being formed by vanadium nitride and/or formed by vanadium carbonitride the upper layer of the scope from surface to 10 μ m, and, the area occupation ratio of the particle of the particle of particle diameter 0.2～2 μ m being made up of described vanadium nitride the upper layer of the scope from surface to 10 μ m and/or particle diameter 0.2～2 μ m being made up of vanadium carbonitride is 1～10%, the surface that is present in the non-grind section of the part beyond described groove portion is 0.7～1.0 quality % to the carbon content the upper layer of the scope of 10 μ m, and be 700～800 (also referred to as " manufacture method 2 ") apart from the Vickers' hardness of the dark position of this surface 50 μ m.

According to the manufacture method 2 that adopts this formation, the moulding starting material that obtain described steel are processed into regulation shape, be in the carbonitriding atmosphere of 2～5 volume % at carbon potential 0.9～1.3, ammonia concentration, at 850～900 ℃, heat more than 4 hours, thus described moulding starting material are implemented to carbonitriding processing, therefore can obtain as the raceway member of bearing component parts 2 of action effect of realizing above-mentioned excellence.

Rolling bearing of the present invention has: inner peripheral surface have the outer ring of groove portion, periphery have groove portion inner ring, be disposed at the multiple rolling bodys between two groove portion of described Internal and external cycle, it is characterized by, at least one in described inner ring, outer ring and rolling body is made up of above-mentioned bearing component parts.

Rolling bearing of the present invention, because at least one in described inner ring, outer ring and rolling body is made up of above-mentioned bearing component parts, therefore shows long lifetime and static load ability and fully dimensional stability fully.

Bearing component parts of the present invention, after the moulding starting material that process by the steel of the vanadium to the chromium that contains 3.2～5.0 quality %, 0.05 quality % is above and less than 0.5 quality % are implemented carbonitriding and are processed, deepfreeze at again obtained intermediate raw material being implemented to-50～-100 ℃ and precision work and obtain, there is the surface of having carried out fine grinding processing, described carbonitriding is treated in carbon potential 0.9～1.3, ammonia concentration are the carbonitriding atmosphere of 2～5 volume % and is heated to 850～900 ℃ of processing of then carrying out chilling, it is characterized by

Be 1.1～1.6 quality % from the surface of having carried out described fine grinding processing to the carbon content the upper layer of the scope of 10 μ m, Vickers' hardness apart from the dark position of described surperficial 50 μ m is 800～940, remained austenite content apart from the dark position of described surperficial 10 μ m is 5～30 volume %, nitrogen content the upper layer of the scope from described surface to 10 μ m is 0.1～1.0 quality %, the particle of particle diameter 0.2～2 μ m that there is the particle of particle diameter 0.2～2 μ m being formed by vanadium nitride and/or formed by vanadium carbonitride the upper layer of the scope from described surface to 10 μ m, and, the area occupation ratio of the particle of the particle of the particle diameter being made up of vanadium nitride 0.2～2 μ m the upper layer of the scope from described surface to 10 μ m and/or particle diameter 0.2～2 μ m being made up of vanadium carbonitride is 1～10%.In addition, so-called from surface to the upper layer of the scope of 10 μ m, be defined as surface and apart from the scope (also referred to as " bearing component parts 3 ") between the dark position of surperficial 10 μ m.

Bearing component parts 3 of the present invention is parts that the intermediate raw material to having implemented described carbonitriding processing has been implemented described deepfreeze.Thus, in bearing component parts of the present invention, Vickers' hardness apart from the dark position of the surface 50 μ m that carried out fine grinding processing is 800～940 (Rockwell C hardness 64～68), and is 5～30 volume % apart from the remained austenite content of the dark position of described surperficial 10 μ m.

Therefore, in bearing component parts 3 of the present invention, martensite volume has increased, and sufficient static load ability has been guaranteed in high yield stress.Thus, according to bearing component parts of the present invention, even if bear larger shock load while bearing in use the rotation in the situation of excessive static load and under the utmost point slow speed of revolution, also can reduce the local set deformation volume in each roller surface of outer inner ring and the contact part of rolling body.

In the present invention, described bearing component parts is the raceway member with the groove portion of having carried out fine grinding processing, wherein preferred, the carbon that described steel contain 0.7～0.9 quality %, the surface from non-grind section that is present in described groove portion part is in addition 0.7～1.0 quality % to the carbon content the upper layer of the scope of 10 μ m, and, be 700～800 apart from the Vickers' hardness of the dark position of the surface 50 μ m of described non-grind section.

In this case, the surface from non-grind section that is present in described groove portion part is in addition 0.7～1.0 quality % to the carbon content the upper layer of the scope of 10 μ m, and, Vickers' hardness apart from the dark position of the surface 50 μ m of described non-grind section is 700～800, therefore can suppress the generation of the over cargurization tissue in non-grind section.

Therefore, as the raceway member of bearing component parts that possesses this formation, except described action effect, also easily bear from outside load, for example, if as the outer ring of rolling bearing, can improve the rolling fatigue life of this rolling bearing, and can give sufficient intensity to this rolling bearing.

Rolling bearing of the present invention has: inner peripheral surface have the outer ring of groove portion, periphery have groove portion inner ring, be disposed at the multiple rolling bodys between two groove portion of described outer inner ring, it is characterized by,

Described outer ring is fixed ring, and is made up of above-mentioned bearing component parts.

Rolling bearing of the present invention is because the outer ring as fixed ring is made up of above-mentioned bearing component parts, and therefore, in rolling bearing, the static load ability of the fixed ring of maximum contact stress maximum is fully guaranteed.Thus, according to rolling bearing of the present invention, can reduce, as the set deformation volume in the outer ring of fixed ring and contact part rolling body, even if described static load or shock load exceed critical load, also can guarantee smooth and easy rotation.

In rolling bearing of the present invention, preferably, described inner ring is for driving circle, and by forming as lower member, described parts, by the chromium that contains 3.2～5.0 quality %, the steel of the vanadium of the above and less than 0.5 quality % of 0.05 quality % obtain, carbon content the upper layer of the scope from surface to 10 μ m is 1.1～1.6 quality %, Vickers' hardness apart from the dark position of surperficial 50 μ m is 740～900 (Rockwell C hardness is 62～67), remained austenite content apart from the dark position of surperficial 10 μ m is 20～55 volume %, nitrogen content the upper layer of the scope from surface to 10 μ m is 0.1～1.0 quality %, the particle of particle diameter 0.2～2 μ m that there is the particle of particle diameter 0.2～2 μ m being formed by vanadium nitride and/or formed by vanadium carbonitride the upper layer of the scope from surface to 10 μ m, and, the area occupation ratio of the particle of the particle of particle diameter 0.2～2 μ m being made up of described vanadium nitride the upper layer of the scope from described surface to 10 μ m and/or particle diameter 0.2～2 μ m being made up of vanadium carbonitride is 1～10%.

Like this, rolling bearing of the present invention is because the remained austenite content apart from the dark position of surperficial 10 μ m of inner ring is 20～55 volume %, even while therefore using this rolling bearing in the lubricating oil that is mixed with impurity, also can relax the impression that generates when this rolling bearing is nipped impurity stress concentration around, also can suppress surperficial starting point damage.Therefore, in this case, can guarantee the life-span in higher impurity oil.

The manufacture method of bearing component parts of the present invention, is characterized by, and comprising:

Front manufacturing procedure, the steel of the vanadium of the chromium that contains 3.2～5.0 quality %, 0.05 quality % is above and less than 0.5 quality % are processed into regulation shape, obtain moulding starting material;

Carbonitriding treatment process, described moulding starting material are implemented to carbonitriding and process and obtain intermediate raw material, described carbonitriding is treated in carbon potential 0.9～1.3, ammonia concentration are the carbonitriding atmosphere of 2～5 volume % heats these moulding starting material the processing of then carrying out chilling at 850～900 ℃;

Deepfreeze operation, to described carbonitriding intermediate raw material after treatment, implements the cooling deepfreeze at-50～-100 ℃ of this intermediate raw material; And

Finishing step, implement precision work by the intermediate raw material to after described deepfreeze operation, obtain following bearing component parts: in described bearing component parts, Vickers' hardness apart from the dark position of surperficial 50 μ m is 800～940 (Rockwell C hardness is 64～68), remained austenite content apart from the dark position of surperficial 10 μ m is 5～30 volume %, nitrogen content the upper layer of the scope from described surface to 10 μ m is 0.1～1.0 quality %, the particle of particle diameter 0.2～2 μ m that there is the particle of particle diameter 0.2～2 μ m being formed by vanadium nitride and/or formed by vanadium carbonitride the upper layer of the scope from described surface to 10 μ m, and, the area occupation ratio of the particle of the particle of particle diameter 0.2～2 μ m being made up of described vanadium nitride the upper layer of the scope from described surface to 10 μ m and/or particle diameter 0.2～2 μ m being made up of vanadium carbonitride is 1～10% (also referred to as " manufacture method 3 ").

In the manufacture method 3 of bearing component parts of the present invention, the moulding starting material that obtained by described steel are implemented to described carbonitriding processing, then further carbonitriding intermediate raw material after treatment is implemented to deepfreeze, and the intermediate raw material after this deepfreeze is implemented to precision work, therefore can make the lip-deep residual austenite of carbonitriding intermediate raw material after treatment become the more martensite of hard.

Therefore, can will make 800～940 (Rockwell C hardness 64～68) apart from the Vickers' hardness of the dark position of surperficial 50 μ m, to make 5～30 volume % apart from the remained austenite content of the dark position of surperficial 10 μ m, nitrogen content the upper layer of the scope from described surface to 10 μ m is made to 0.1～1.0 quality %, the particle of particle diameter 0.2～2 μ m that has the particle of particle diameter 0.2～2 μ m being formed by vanadium nitride and/or formed by vanadium carbonitride the upper layer of the scope from described surface to 10 μ m, and, the area occupation ratio of the particle of the particle of particle diameter 0.2～2 μ m being made up of described vanadium nitride the upper layer of the scope from described surface to 10 μ m and/or particle diameter 0.2～2 μ m that is made up of vanadium carbonitride is made to 1～10%.

Therefore,, by the bearing component parts that adopts the manufacture method of this formation to obtain, in the case of the fixed ring as in rolling bearing, can realize the action effect of above-mentioned bearing component parts.

The manufacture method of raceway member of the present invention, is as the manufacture method of the raceway member of above-mentioned bearing component parts, it is characterized by, and comprising:

Carbonitriding treatment process, described moulding starting material are implemented carbonitriding processing and obtained intermediate raw material, it is in the carbonitriding atmosphere of 2～5 volume % that described carbonitriding is treated at carbon potential 0.9～1.3, ammonia concentration, and these moulding starting material are heated and within 4 hours, then carry out above the processing of chilling at 850～900 ℃;

Finishing step, the part of the described roller surface of formation by the intermediate raw material to after described deepfreeze operation is implemented fine grinding processing, form described groove portion, obtain following raceway member: in described raceway member, be more than 1.1 quality % and less than 1.6 quality % from the surface of described groove portion to the carbon content the upper layer of the scope of 10 μ m, Vickers' hardness apart from the dark position of described surperficial 50 μ m is 800～940, remained austenite content apart from the dark position of described surperficial 10 μ m is 5～30 volume %, nitrogen content the upper layer of the scope from described surface to 10 μ m is 0.1～1.0 quality %, the particle of particle diameter 0.2～2 μ m that there is the particle of particle diameter 0.2～2 μ m being formed by vanadium nitride and/or formed by vanadium carbonitride the upper layer of the scope from surface to 10 μ m, and, the area occupation ratio of the particle of the particle of the particle diameter being made up of vanadium nitride 0.2～2 μ m the upper layer of the scope from surface to 10 μ m and/or particle diameter 0.2～2 μ m being made up of vanadium carbonitride is 1～10%, the surface from non-grind section that is present in described groove portion part is in addition 0.7～1.0 quality % to the carbon content the upper layer of the scope of 10 μ m, and the Vickers' hardness apart from the dark position of the surface 50 μ m of described non-grind section was 700～800 (being called " manufacture method 4 ").

According to the manufacture method 4 of the raceway member of this formation of employing, the moulding starting material at least in the part that forms roller surface with the raceway member of grind that obtain described steel are processed into regulation shape, implement described carbonitriding processing, then further carbonitriding intermediate raw material after treatment is implemented to deepfreeze, and intermediate raw material after this deepfreeze is implemented to precision work, therefore can make the residual austenite in the surface of part of the formation roller surface of carbonitriding intermediate raw material after treatment become the more martensite of hard.

Therefore, more than 1.1 quality % can being made to the carbon content the upper layer of the scope of 10 μ m in the surface from groove portion of raceway member and less than 1.6 quality %, to make 800～940 apart from the Vickers' hardness of the dark position of described surperficial 50 μ m, to make 5～30 volume % apart from the remained austenite content of the dark position of described surperficial 10 μ m, nitrogen content the upper layer of the scope from described surface to 10 μ m is made to 0.1～1.0 quality %, the particle of particle diameter 0.2～2 μ m that has the particle of particle diameter 0.2～2 μ m being formed by vanadium nitride and/or formed by vanadium carbonitride the upper layer of the scope from described surface to 10 μ m, and the area occupation ratio of the particle of the particle of the particle diameter being made up of vanadium nitride 0.2～2 μ m the upper layer of the scope from described surface to 10 μ m and/or particle diameter 0.2～2 μ m that is made up of vanadium carbonitride is made to 1～10%, the surface from non-grind section that makes to be present in the part beyond described groove portion is 0.7～1.0 quality % to the carbon content the upper layer of the scope of 10 μ m, and will make 700～800 apart from the Vickers' hardness of the dark position of this surface 50 μ m.

Therefore, by adopting the bearing component parts that the manufacture method of this formation obtains can realize above-mentioned action effect.

Invention effect

According to bearing component parts of the present invention and manufacture method thereof, can be achieved as follows excellent effect, that is, the long lifetime of rolling bearing can be realized, and sufficient static load ability and sufficient dimensional stability can be guaranteed.In addition, according to rolling bearing of the present invention, can realize the long lifetime and show sufficient static load ability and the effect of sufficient this excellence of dimensional stability.

Accompanying drawing explanation

Fig. 1 represents that the i.e. conduct of an example of the bearing component parts of first embodiment of the invention and the second embodiment has the summary description figure of the spot contact bearing of the rolling bearing of inner ring, outer ring and ball;

Fig. 2 A is a process picture sheet that example is the manufacture method of Internal and external cycle that represents the bearing component parts of first embodiment of the invention;

Fig. 2 B represents that the bearing component parts of second embodiment of the invention is the process picture sheet of the manufacture method of outer ring;

Fig. 3 represents that experiment numbers 1-1 is heat-treat condition while manufacturing of the Internal and external cycle of embodiment 1-1 and the line chart of the heat-treat condition of experiment numbers 2-1;

Fig. 4 represents that experiment numbers 1-2 is heat-treat condition while manufacturing of the Internal and external cycle of embodiment 1-2 and embodiment 1-4 and the line chart of the heat-treat condition of experiment numbers 2-12;

Fig. 5 represents that experiment numbers 1-3 is heat-treat condition while manufacturing of the Internal and external cycle of embodiment 1-3 and the line chart of the heat-treat condition of experiment numbers 2-13;

Fig. 6 represents that experiment numbers 1-4 is heat-treat condition while manufacturing and while using the rolling body of the spot contact bearing of this Internal and external cycle to manufacture of the Internal and external cycle of comparative example 1-1 and comparative example 1-9 and the line chart of the heat-treat condition of experiment numbers 2-6 and comparative example 2-8;

Fig. 7 represents that experiment numbers 1-5 is heat-treat condition while manufacturing of the Internal and external cycle of comparative example 1-2 and the line chart of the heat-treat condition of experiment numbers 2-7;

Fig. 8 is while representing that experiment numbers 1-6 is the manufacture of Internal and external cycle of comparative example 1-3 and the line chart of the heat-treat condition of heat-treat condition while using the rolling body of the spot contact bearing of the Internal and external cycle of embodiment 1-1～1-3 and comparative example 1-2～1-7 to manufacture and experiment numbers 2-2;

Fig. 9 represents that experiment numbers 1-7 is heat-treat condition while manufacturing of the Internal and external cycle of comparative example 1-4 and the line chart of the heat-treat condition of experiment numbers 2-8;

Figure 10 represents that experiment numbers 1-8 is heat-treat condition while manufacturing of the Internal and external cycle of comparative example 1-5 and the line chart of the heat-treat condition of experiment numbers 2-9;

Figure 11 represents that experiment numbers 1-9 is heat-treat condition while manufacturing of the Internal and external cycle of comparative example 1-6 and the line chart of the heat-treat condition of experiment numbers 2-10;

Figure 12 represents that experiment numbers 1-10 is heat-treat condition while manufacturing of the Internal and external cycle of comparative example 1-7 and the line chart of the heat-treat condition of experiment numbers 2-11;

Figure 13 (A) is that the accompanying drawing that represents the reflection of the carbon of the inner peripheral surface of embodiment 1-1 substitutes photo; (B) be that the accompanying drawing that represents the reflection of the nitrogen of the inner peripheral surface of embodiment 1-1 substitutes photo; And (C) be that the accompanying drawing that represents the reflection of the vanadium of the inner peripheral surface of embodiment 1-1 substitutes photo;

Figure 14 is the schematic diagram that summarily represents the determination unit of the raceway circle depth of indentation of test example 1-1;

Figure 15 is the coordinate diagram that represents the relation of test period and cumulative damage probability in test example 1-2;

Figure 16 is the coordinate diagram that represents the relation of aging time and size changing rate in test example 1-3;

Figure 17 represents that experiment numbers 1-11 is the line chart of the heat-treat condition of embodiment 1-5 and the heat-treat condition of embodiment 2-3;

Figure 18 represents that experiment numbers 1-12 is the line chart of the heat-treat condition of embodiment 1-6;

Figure 19 represents that experiment numbers 1-13 is the line chart of the heat-treat condition of embodiment 1-7;

Figure 20 represents that experiment numbers 1-14 is the line chart of the heat-treat condition of comparative example 1-8 and the heat-treat condition of comparative example 2-10;

Figure 21 represents that experiment numbers 1-15 is the line chart of the heat-treat condition of comparative example 1-10 and the heat-treat condition of comparative example 2-9;

Figure 22 represents that experiment numbers 1-16 is the line chart of the heat-treat condition of comparative example 1-11 and the heat-treat condition of comparative example 2-11;

Figure 23 represents that experiment numbers 1-17 is the line chart of the heat-treat condition of comparative example 1-12 and the heat-treat condition of comparative example 2-12;

Figure 24 is that the accompanying drawing that represents the result on the groove portion surface (grind section) of the raceway member that utilizes electron microscope observation embodiment 1-4 substitutes photo;

Figure 25 is that the accompanying drawing of the surperficial result of the groove portion surface (grind section (in figure, A)) that represents the raceway member that utilizes electron microscope observation embodiment 1-4 and non-grind section (in figure, B) substitutes photo;

Figure 26 is that the accompanying drawing of the surperficial result of the groove portion surface (grind section (in figure, C)) that represents the raceway member that utilizes electron microscope observation comparative example 1-12 and non-grind section (in figure, D) substitutes photo;

Figure 27 is the line chart that represents the heat-treat condition of experiment numbers 2-3;

Figure 28 is the line chart that represents the heat-treat condition of experiment numbers 2-4;

Figure 29 is the line chart that represents the heat-treat condition of experiment numbers 2-5;

Embodiment

(bearing component parts and rolling bearing)

(the first embodiment)

Utilize accompanying drawing to describe the bearing component parts of first embodiment of the invention below.Fig. 1 is the summary description figure of spot contact bearing of rolling bearing of inner ring, outer ring and ball representing as having one of bearing component parts of first embodiment of the invention example.

Spot contact bearing 10 possesses: periphery have the inner ring 1 of groove portion 1a, inner peripheral surface have groove portion 2a outer ring 2, be disposed at the multiple rolling bodys of conduct between two groove portion 1a, the 2a of Internal and external cycle 1,2 ball 3, on Zhou Fangxiang, keep the retainer 4 of multiple balls 3 every predetermined distance.

The surface of groove portion 1a, end face 1b, shoulder face 1c and the inner peripheral surface 1d of inner ring 1 is the grind section of having carried out fine grinding processing.The chamfering 1f of the outer circumferential side of the inner ring 1 of the chamfering 1e of the inner circumferential side of the inner ring 1 of the cross section R shape being connected with end face 1b and the inner peripheral surface 1d of inner ring 1 on the other hand,, the cross section rectilinear form being connected with end face 1b and shoulder face 1c forms as not carrying out the non-grind section of fine grinding processing.

The surface of groove portion 2a, end face 2b, shoulder face 2c and the periphery 2d of outer ring 2 is the grind section of having carried out fine grinding processing.The chamfering 2f of the inner circumferential side of the outer ring 2 of the chamfering 2e of the outer circumferential side of the outer ring 2 of the cross section R shape being connected with end face 2b and the periphery 2d of outer ring 2 on the other hand,, the cross section rectilinear form being connected with end face 2b and shoulder face 2c forms as not carrying out the non-grind section of fine grinding processing.

The grind section that comprises groove portion 1a, 2a of Internal and external cycle 1,2 and ball 3 hardness apart from the dark position of surperficial 50 μ m separately, reduce the viewpoint of the size of the impression generating from use spot contact bearing 10 the lubricating oil that is mixed with impurity time in the time nipping above-mentioned impurity, more than Vickers' hardness 740 (Rockwell C hardness 62), from preventing the viewpoint of embrittlement, below Vickers' hardness 900 (Rockwell C hardness 67).

In addition, in this manual, Vickers' hardness refers to, cut off above-mentioned inner ring along depth direction from surface after, apart from the above-mentioned surperficial 50 dark positions of μ m, is pressed into Vickers pressure head and the value measured.In addition, in this manual, Rockwell C hardness refers to, by measured Vickers' hardness being converted to the value of trying to achieve.

The grind section that comprises groove portion 1a, 2a of Internal and external cycle 1,2 and ball 3 remained austenite content (skin section remained austenite content) apart from the dark position of surperficial 10 μ m separately, from relaxing the viewpoint of the surface damage portions such as impression stress concentration around, be more than 20 volume %, from obtaining the viewpoint of sufficient surface hardness, be below 55 volume %.

In addition, the grind section that comprises groove portion 1a, 2a of Internal and external cycle 1,2 and ball 3 inside is separately (than being formed at the darker region of surperficial carbonitrided case, as an example, the in the situation that of model 6206 bearing, apart from the above dark position of surperficial 1.5mm) remained austenite content (inner remained austenite content), from obtaining the viewpoint of good dimensional stability, be below 15 volume %.The lower limit of inner remained austenite content can suitably be set, for example, and more than can being made as 3 volume %.Thus, can improve dimensional stability.

In addition, in this manual, " dimensional stability " refers to, with respect to the stability of ageing dimensional change.

The grind section that comprises groove portion 1a, 2a of Internal and external cycle 1,2 and ball 3 separately from surface to the upper layer of the scope of 10 μ m, have the particle being formed by vanadium nitride and/or the particle being formed by vanadium carbonitride.The particle diameter of above-mentioned particle, from by the dispersion-strengthened viewpoint that improves yielding stress based on Ao Luowan (orowan) mechanism, comprise particle diameter more than 0.2 μ m, from bring out the viewpoint of particle coarsening by Ostwald (Ostwald) slaking, be preferably below 2 μ m.In addition, grind section from surface to the upper layer of the scope of 10 μ m, also contain the particle of particle diameter less than 0.2 μ m.

In addition, in the grind section that comprises groove portion 1a, 2a and ball 3 surface separately of Internal and external cycle 1,2, cementite and M have been separated out ₇c ₃type carbide and M ₂₃c ₆type carbide.

Internal and external cycle 1, 2 comprise groove portion 1a, the area occupation ratio of the particle of the particle of particle diameter 0.2～2 μ m being formed by above-mentioned vanadium nitride the upper layer of the grind section of 2a and ball 3 scope from surface to 10 μ m separately and/or particle diameter 0.2～2 μ m being formed by vanadium carbonitride, from guarantee the viewpoint of sufficient static load ability by improving yielding stress based on Ao Luowan mechanism dispersion-strengthened, be more than 1%, from infiltrating the required carbon amount of guaranteeing by suppressing excessive nitrogen to steel, obtain Vickers' hardness (apart from the Vickers' hardness of the dark position of surperficial 50 μ m) 740～900 (the Rockwell C hardness 62～67) as bearing component parts, and realize long lifetime, and the viewpoint of guaranteeing sufficient static load ability is set out, be below 10%.In addition, in this manual, the area occupation ratio of above-mentioned particle refers to, the area occupation ratio of the particle that the particle of the particle of the particle diameter being made up of vanadium nitride 0.2～2 μ m the upper layer of the scope from surface to 10 μ m and particle diameter 0.2～2 μ m being made up of vanadium carbonitride is added together.

The content of the carbon the upper layer of the grind section that comprises groove portion 1a, 2a of Internal and external cycle 1,2 and ball 3 scope from surface to 10 μ m separately, from guaranteeing to have to the remained austenite content of the alleviation effects of the stress concentration of the surface damage portions such as above-mentioned impression and making the viewpoint of high surface hardness, be more than 1.1 quality %, from the thick precipitate by reducing the carbide above-mentioned upper layer (for example, particle diameter exceedes the precipitate of 10 μ m) amount further improve the viewpoint in life-span and set out, be below 1.6 quality %.

Internal and external cycle 1, 2 comprise groove portion 1a, the grind section of 2a and ball 3 separately from surface to the content of the nitrogen of the upper layer of the scope of 10 μ m, from by the dispersion-strengthened yielding stress that improves based on Ao Luowan mechanism, thereby guarantee sufficient static load ability, and the viewpoint that obtains sufficient ultimate compression strength is set out, be more than 0.1 quality %, from by suppressing excessive nitrogen to infiltrating steel and guaranteeing required carbon amount, obtain Vickers' hardness (apart from the Vickers' hardness of the dark position of surperficial 50 μ m) 740～900 (the Rockwell C hardness 62～67) as bearing component parts, and realize long lifetime, and guarantee sufficient static load ability, the viewpoint that simultaneously prevents the embrittlement that excessive nitrogenize causes is set out, be below 1.0 quality %.

In addition, in an embodiment of the first embodiment, the grind section that comprises groove portion 1a, 2a from surface to the upper layer of the scope of 10 μ m, also can have the particle being made up of nitride (nitride particles) below particle diameter 500nm, the area occupation ratio of the precipitate of the nitrogenate in this upper layer can be also 5～20%.In this case, over cargurization tissue obtained inhibition, can obtain sufficient ultimate compression strength.

In addition, in an embodiment of the first embodiment, the area occupation ratio of the precipitate of the nitrogenate the upper layer of the scope from surface to 10 μ m of the grind section that comprises groove portion 1a, 2a, from suppress non-grind section over cargurization tissue generation and obtain the viewpoint of sufficient ultimate compression strength, be preferably more than 5%, from preventing the viewpoint of the embrittlement that excessive nitrogenize causes, be preferably below 20%.

In addition, in an embodiment of the first embodiment, the content of the carbon the upper layer of the scope from surface to 10 μ m of the non-grind section of the chamfering 2f of the chamfering 2e of the chamfering 1f of the chamfering 1e of the inner circumferential side that comprises inner ring, the outer circumferential side of inner ring, the outer circumferential side of outer ring and the inner circumferential side of outer ring, from obtaining for guaranteeing the viewpoint as the hardness of the static strength of bearing, be more than 0.7 quality %, the viewpoint that obtains sufficient ultimate compression strength from suppressing the generation of the over cargurization tissue non-grind section is below 1.0 quality %.

In addition, in an embodiment of the first embodiment, the non-grind section of the chamfering 2f of the chamfering 2e of the chamfering 1f of the chamfering 1e of the inner circumferential side that comprises inner ring, the outer circumferential side of inner ring, the outer circumferential side of outer ring and the inner circumferential side of outer ring from surface to the Vickers' hardness of the dark position of 50 μ m, as spot contact bearing, from obtaining the viewpoint of sufficient intensity, being more than 700, from guaranteeing the viewpoint of sufficient toughness, is below 800.

(manufacture method of bearing component parts)

Then, the manufacture method of the bearing component parts to first embodiment of the invention describes.Fig. 2 A is that one of bearing component parts of first embodiment of the invention example is the process picture sheet of the manufacture method of Internal and external cycle.

First, to the carbon by containing 0.7～0.9 quality %, the chromium of 3.2～5.0 quality %, ring-type starting material 23 (with reference to Fig. 2 A (a)) the enforcement machining of more than 0.05 quality % and the outer ring of the steel of the vanadium of less than 0.5 quality % formation etc., be processed into regulation shape, obtain the moulding starting material 24 (front manufacturing procedure) (with reference to Fig. 2 A (b)) of outer ring, the moulding starting material 24 of described outer ring are forming respectively roller surface 21a, end face 21b, the part of shoulder face 21c and periphery 21d has grind, and there is the chamfering 21e of the outer circumferential side of the outer ring of the cross section R shape of not grinding being connected with end face 21b and periphery 21d, the chamfering 21f of the inner circumferential side of the outer ring of the cross section rectilinear form not grinding being connected with end face 21b and shoulder face 21c.In addition, ring-type starting material 13 (with reference to Fig. 2 A (f)) to the inner ring being made up of the steel identical with the ring-type starting material 23 of outer ring are implemented machining etc., be processed into regulation shape, obtain the moulding starting material 14 (front manufacturing procedure) (with reference to Fig. 2 A (g)) of inner ring, the moulding starting material 14 of described inner ring are forming respectively roller surface 11a, end face 11b, the part of shoulder face 11c and inner peripheral surface 11d has grind, and there is the chamfering 11e of the inner circumferential side of the inner ring of the cross section R shape of not grinding being connected with end face 11b and inner peripheral surface 11d, the chamfering 11f of the outer circumferential side of the inner ring of the cross section rectilinear form not grinding being connected with end face 11b and shoulder face 11c.

As above-mentioned steel, the vanadium that can use the above and less than 0.5 quality % of silicon, the manganese of 0.05～0.7 quality %, the chromium of 3.2～5.0 quality %, the molybdenum of 0.1～1.0 quality %, the 0.05 quality % of the carbon that contains 0.7～0.9 quality %, 0.05～0.70 quality %, all the other be the steel of iron and inevitable impurity.

According to this steel, the amount of the thick eutectic carbides of separating out when lip-deep steel processed separately of Internal and external cycle reduces, and can suppress the fatigure failure of bearing, and after quenching, after carbonitriding and tempering, can guarantee sufficient hardness.

In addition, according to above-mentioned steel, in order to improve the life-span of rolling bearing, even in the case of by Internal and external cycle carrying out separately grind after the remained austenite content apart from the dark position of surperficial 10 μ m make 55 volume %, also sufficient hardness can be guaranteed, and dimensional stability can be improved.

In addition, conventionally, as steel, the steel that formed by SUJ2 at use bearing steel, in the time that inner remained austenite content exceedes 5 volume %, there is the tendency of dimensional stability variation.But, the chromium that contains above-mentioned 3.2～5.0 quality % in use, more than 0.05 quality % and the steel of the vanadium of less than 0.5 quality %, by by the inside of the groove portion of Internal and external cycle (than being formed at the surperficial darker region of brinelling layer, as an example, the in the situation that of model 6206 bearing, apart from the above dark position of surperficial 1.5mm) remained austenite content (inner remained austenite content) make below 15 volume %, can obtain good dimensional stability.

In above-mentioned steel, carbon is the element of the following effect of performance, that is, in the time carrying out the carbonitriding treatment process of next procedure, make the hardness of steel increase, and obtains the inside hardness for guaranteeing intensity.In addition, carbon is the element of the following effect of performance,, processes the carbide of not solid solutions remaining a large amount of in front steel by being formed in carbonitriding described later that is, and the also state of the carbide of remaining fine and a large amount of not solid solution after carbonitriding is processed, can improve rolling fatigue life.

The content of contained carbon in above-mentioned steel, the remaining not viewpoint of the carbide of solid solution fully from steel, be more than 0.7 quality %, from obtaining fully carbonitriding processibility before treatment, and the viewpoint that suppresses the generation of the thick eutectic carbides that easily becomes fatigure failure starting point in the time manufacturing steel is set out, and is below 0.9 quality %.

In addition, in above-mentioned steel, chromium is the element of the following effect of performance,, by in the carbonitriding stage before treatment, when being created on carbonitriding and processing, as the carbide of separating out a large amount of not solid solution that core plays a role, and on surperficial carbonitrided case after carbonitriding, separate out fine carbide (M ₇c ₃type carbide, M ₂₃c ₆type carbide), fine carbonitride (M ₇(C, N) ₃type carbonitride, M ₂₃(C, N) ₆type carbonitride) and fine nitride (CrN, VN), improves the rolling fatigue life of bearing component parts.In addition, chromium carries out the promotion of the nitrogenizing reaction in steel most surface layer that the generation of carbonitride in steel and nitride promotes to cause, and carries out the inhibition (inhibition of the generation of over cargurization tissue) of carburization reaction.

From the viewpoint in order to obtain above-mentioned effect, in steel, the content of contained chromium is more than 3.2 quality %, from easily becoming the viewpoint of inhibition of generation of eutectic carbides of fatigure failure starting point and the viewpoint reducing costs, is below 5.0 quality %.

In above-mentioned steel, vanadium is the element very strong with the avidity of carbon, is the element that forms carbide.In addition, the vanadium carbide being generated by carbon and vanadium, compared with molybdenum carbide, solid solubility temperature is high, therefore in the temperature range of the carbonitriding processing in the time of the manufacture of bearing component parts of the present invention, the not solid solution of many vanadium carbides existing before carbonitriding is processed, is present in steel as the vanadium carbide of not solid solution.Carbide (VC) when the vanadium carbide of this not solid solution is processed as carbonitriding, carbonitride (V (C,) and nitride ((Cr N), V) N) etc. the core of separating out play a role, and contribute to the miniaturization of the precipitates such as above-mentioned carbide, carbonitride, nitride, can improve hardness and the rolling fatigue life of steel.And vanadium is not second to the chromium in steel, the promotion of nitrogenizing reaction and the inhibition of carburization reaction (inhibition of the generation of over cargurization tissue) in the steel most surface layer that the generation that can carry out carbonitride and nitride promotes to cause.

From the viewpoint in order to obtain above-mentioned effect, in steel, the content of contained vanadium is more than 0.05 quality %, from the viewpoint of fully guaranteeing solid solution carbon amount and fully guaranteeing remained austenite content by suppressing the generation of vanadium carbide, is less than 0.5 quality %.

In above-mentioned steel, silicon is the necessary element of deoxidation during for the refining of steel.In addition, silicon has and is difficult to solid solution in the character of carbide, and therefore silicon is the element with the effect that suppresses the thick growth of carbide.

From obtaining the viewpoint of above-mentioned effect, in steel, the content of contained silicon is more than 0.05 quality %, from fully obtaining the viewpoint of carbonitriding processibility before treatment, is below 0.70 quality %.

In above-mentioned steel, manganese is the element that makes the stabilization of austenite in steel.In addition, manganese is by increasing the element that in steel, contained amount can easily make remained austenite content increase.

From obtaining the viewpoint of above-mentioned effect, in steel, the content of contained manganese is more than 0.05 quality %, thereby increase and make Carbide Precipitation improve the hardness of steel and improve the viewpoint of rolling fatigue life and obtain the viewpoint of sufficient hot workability and machinability from the amount of the carbide that makes the not solid solution steel, be below 0.7 quality %, be preferably below 0.50 quality %.

In above-mentioned steel, molybdenum is the element stronger than chromium with the avidity of carbon, is the element relevant to the generation of carbide and carbonitride.In addition, molybdenum is that carbide at the temperature of the carbonitriding processing while making to manufacture bearing component parts of the present invention and the solid solubility temperature of carbonitride rise, and makes the carbide of not solid solution and the element that carbonitride increases.Therefore, molybdenum is that fine carbide amount and the carbonitride amount for making carbonitriding surperficial carbonitrided case after treatment increases, and the important element that makes the hardness of steel increase.In addition, molybdenum improves the hardenability of steel, and the remained austenite content in steel is increased.In addition, molybdenum is to make carbide (M ₂₃c ₆type carbide) and carbonitride (M ₂₃(C, N) ₆type carbonitride) element of separating out efficiently.

From obtaining the viewpoint of above-mentioned effect, in steel, the content of contained molybdenum is more than 0.10 quality %, from the viewpoint reducing costs and the viewpoint that suppresses the generation of the thick eutectic carbides of the starting point that becomes fatigure failure, is below 1.0 quality %.

Then, moulding starting material 24 to obtained outer ring and the moulding starting material 14 of inner ring are implemented thermal treatment, and making it be hardened to the moulding starting material 24 of this outer ring and the moulding starting material 14 of inner ring surface hardness separately becomes for example Vickers' hardness (Hv) more than 700 (with reference to Fig. 2 A (c) and (d), Fig. 2 A (h) and (i)).

In this heat treatment step, first, by above-mentioned moulding starting material carbon potential be 0.9～1.3 and ammonia concentration be in the carbonitriding atmosphere of 2～5 volume %, these moulding starting material are heated to 850～900 ℃ to be kept,,, carry out chilling (carbonitriding treatment process) (with reference to Fig. 2 A (c) and Fig. 2 A (h)) thereafter.

The carbon potential of carbonitriding atmosphere, the viewpoint of giving sufficient hardened layer from forming the cementation zone of sufficient carburized depth, be more than 0.9, from the area occupation ratio of outer ring 2 and inner ring 1 precipitate that comprises above-mentioned vanadium nitride or vanadium carbonitride separately being made to above-mentioned scope and being suppressed the viewpoint of the generation of over cargurization tissue, be below 1.3.

In addition, the ammonia concentration of carbonitriding atmosphere, from suppressing the viewpoint of generation of over cargurization tissue, is more than 2 volume %, from preventing the viewpoint of the embrittlement that excessive nitrogenize causes, is below 5 volume %.

The heating of carbonitriding atmosphere keeps temperature, from forming the viewpoint of sufficient hardened layer, be more than 850 ℃, the viewpoint of separating out that suppresses the generation of over cargurization tissue to infiltrating bearing component parts and suppress thick carbide from suppressing excessive carbon, is below 900 ℃.

In addition, the heating hold-time, from obtain the viewpoint of sufficient carburized depth the strengthening of upper layer, is more than 4 hours.

Chilling is undertaken by the oil cooling in the oil bath of cooling oil.Conventionally, as long as the oil bath temperature of cooling oil is 60～180 ℃.

Then, above-mentioned carbonitriding intermediate raw material after treatment is heated to 160 ℃ of above temperature and the temper (with reference to Fig. 2 A (d) and Fig. 2 A (i)) (temper operation) that keeps.

The heating of temper keeps temperature, recovers the viewpoint of martensitic toughness from quench treatment, is more than 160 ℃, and the viewpoint of decomposing from suppressing residual austenite, is below 250 ℃.

Thereafter, the part that forms respectively roller surface 21a, end face 21b, shoulder face 21c and periphery 21d of the moulding starting material 24 (intermediate raw material) to the outer ring after temper is implemented attrition process, and roller surface 21a is implemented to superfinishing, be finish-machined to specified accuracy (with reference to Fig. 2 A (e)).

So just can obtain target outer ring 21.At this, roller surface 21a, end face 21b, shoulder face 21c and periphery 21d form as grind section, and in this outer ring 21, the chamfering 21f of the chamfering 21e of the outer circumferential side of outer ring and the inner circumferential side of outer ring forms as the non-grind section of not grinding.

In addition, equally, roller surface 11a, end face 11b, shoulder face 11c and the inner peripheral surface 11d of the moulding starting material 14 (intermediate raw material) to the inner ring after thermal treatment implement attrition process, and roller surface 11a is implemented to superfinishing, be finish-machined to specified accuracy (with reference to Fig. 2 A (j)).

So just can obtain target inner ring 11.In this inner ring 11, roller surface 11a, end face 11b, shoulder face 11c and inner peripheral surface 11d form as grind section, and in this inner ring 11, the chamfering 11f of the chamfering 11e of the inner circumferential side of inner ring and the outer circumferential side of inner ring forms as the non-grind section of not grinding.

(variation)

In the spot contact bearing 10 as rolling bearing shown in Fig. 1, as long as at least one the bearing component parts that is first embodiment of the invention in inner ring, outer ring and ball.

This spot contact bearing 10, as outer ring, possesses the outer ring 21 (for example,, with reference to Fig. 2 A (e)) as the bearing component parts of first embodiment of the invention, on the other hand, also can possess the inner ring different from the present invention, or, as inner ring, as the inner ring 11 of the bearing component parts of first embodiment of the invention (for example possess, with reference to Fig. 2 A (j)), on the other hand, also can possess the outer ring different from the present invention.

(the second embodiment)

(bearing component parts and possess the rolling bearing of this bearing component parts)

Utilize accompanying drawing to describe the outer ring of the bearing component parts as second embodiment of the invention below.About the second embodiment, with the example of the rolling bearing of the first embodiment similarly, also utilize Fig. 1 to describe.That is, same as label to same parts use, below, describe based on Fig. 1.Fig. 1 is the summary description figure of structure of spot contact bearing of rolling bearing of bearing component parts (outer ring) representing as possessing second embodiment of the invention.

Same with the first embodiment, the spot contact bearing 10 of the second embodiment possesses: inner peripheral surface have the outer ring 2 of groove portion 2a, periphery have groove portion 1a inner ring 1, be disposed at the ball 3 of the multiple rolling bodys of conduct between two groove portion 1a, the 2a of Internal and external cycle 1,2 and on Zhou Fangxiang, keep the retainer 4 of multiple balls 3 every predetermined distance.

The surface of groove portion 2a, end face 2b, shoulder face 2c and the periphery 2d of outer ring 2 is the grind section of having carried out fine grinding processing.

The chamfering 2f of the inner circumferential side of the outer ring 2 of the chamfering 2e of the outer circumferential side of the outer ring 2 of the cross section R shape being connected with end face 2b and the periphery 2d of outer ring 2 on the other hand,, the cross section rectilinear form being connected with end face 2b and shoulder face 2c forms as not carrying out the non-grind section of fine grinding processing.

In addition, the surface of the groove portion 1a of inner ring 1, end face 1b, shoulder face 1c and inner peripheral surface 1d is the grind section of having carried out fine grinding processing.The chamfering 1f of the outer circumferential side of the inner ring 1 of the chamfering 1e of the inner circumferential side of the inner ring 1 of the cross section R shape being connected with end face 1b and the inner peripheral surface 1d of inner ring 1 on the other hand,, the cross section rectilinear form being connected with end face 1b and shoulder face 1c forms as not carrying out the non-grind section of fine grinding processing.

In spot contact bearing 10, outer ring 2 is fixed ring, and inner ring 1 is for driving circle.

And in the time establishing the diameter of ball 3 and be Bd, the radius-of-curvature of the roller surface of the groove portion 1a of inner ring 1 is 0.505Bd, the radius-of-curvature of the roller surface of the groove portion 2a of outer ring 2 is 0.53Bd.Like this, in spot contact bearing 10, compared with the radius-of-curvature of inner ring 1, the radius-of-curvature of outer ring 2 is large, and therefore the maximum contact stress between maximum contact stress ratio inner ring 1 and the ball 3 between outer ring 2 and ball 3 is large.

Therefore,, in outer ring 2, compared with inner ring 1, by reducing remained austenite content, improved static load ability.Thus, in outer ring 2, realized the inhibition of the generation of tension set.

On the other hand, in inner ring 1, compared with outer ring 2, by increasing remained austenite content, relaxed the impression that generates when nipping impurity stress concentration around.Thus, in inner ring 1, realized the raising in life-span in impurity oil.

Outer inner ring 2,1 all by the chromium from containing 3.2～5.0 quality %, more than 0.05 quality % and the parts that obtain of the steel of the vanadium of less than 0.5 quality % form.

Be in outer ring 2 at fixed ring, the remained austenite content apart from the dark position of surperficial 10 μ m of the grind section that comprises groove portion 2a is 5～30 volume %, and compared with the grind section that comprises groove portion 1a of inner ring 1, above-mentioned remained austenite content is few.Thus, in outer ring 2, martensite volume is many, and sufficient static load ability has been guaranteed in therefore high yield stress.

Like this, in outer ring 2, the remained austenite content apart from the dark position of surperficial 10 μ m of the grind section that comprises groove portion 2a is more than 5 volume %, therefore as outer ring, has guaranteed sufficient life performance.In addition, the remained austenite content apart from the dark position of surperficial 10 μ m of groove portion 2a is below 30 volume %, therefore as outer ring, has guaranteed sufficient static load ability.

Therefore, in the case of the load maximum of the maximum contact stress of spot contact bearing 10, in the outer ring 2 as fixed ring, also guarantee sufficient static load ability, the set deformation volume that therefore can reduce each roller surface of outer inner ring and the contact part of rolling body, can maintain round and smooth rotation.

In outer ring 2, the hardness apart from the dark position of surperficial 50 μ m of the grind section that comprises groove portion 2a, from guarantee the viewpoint of sufficient life-span and static load ability as outer ring, more than Vickers' hardness 800 (Rockwell C hardness 64), from suppressing embrittlement and guaranteeing the viewpoint of sufficient toughness as bearing, below Vickers' hardness 940 (Rockwell C hardness 68).

In addition, in an embodiment of the second embodiment, the grind section that comprises groove portion 2a from surface to the upper layer of the scope of 10 μ m, also can have the particle being made up of nitride (nitride particles) below particle diameter 500nm, the area occupation ratio of the precipitate that contains nitride in this upper layer can be also 5～20%.In this case, suppress the generation of over cargurization tissue, can obtain sufficient ultimate compression strength.

In addition, in an embodiment of the second embodiment, the area occupation ratio of the precipitate that contains nitride the upper layer of the scope from surface to 10 μ m of the grind section that comprises groove portion 2a, from obtaining the viewpoint of sufficient ultimate compression strength, be preferably more than 5%, from preventing the viewpoint of the embrittlement that excessive nitrogenize causes, be preferably below 20%.

In addition, in an embodiment of the second embodiment, the non-grind section of the chamfering 2f of the inner circumferential side of the chamfering 2e of the outer circumferential side that comprises outer ring 2 and outer ring 2 from surface to the content of the carbon of the upper layer of the scope of 10 μ m, from obtaining for guaranteeing the viewpoint as the hardness of the static strength of bearing, be more than 0.7 quality %, from suppress non-grind section over cargurization tissue generation and obtain the viewpoint of sufficient ultimate compression strength, be below 1.0 quality %.

In addition, in an embodiment of the second embodiment, the Vickers' hardness apart from the dark position of surperficial 50 μ m of the non-grind section of the chamfering 2f of the inner circumferential side of the chamfering 2e of the outer circumferential side that comprises outer ring 2 and outer ring 2, from obtaining the viewpoint as the sufficient intensity of spot contact bearing, be more than 700, from guaranteeing the viewpoint of sufficient toughness, be below 800.

On the other hand, be in inner ring 1 driving circle, the remained austenite content apart from the dark position of surperficial 10 μ m of the grind section that comprises its groove portion 1a, relax the viewpoint of the stress concentration around the impression generating when nipping above-mentioned impurity from use spot contact bearing 10 the lubricating oil that is mixed with impurity time, be more than 20 volume %, from obtaining the viewpoint as the sufficient surface hardness of inner ring, be below 55 volume %.

In addition, in inner ring 1, the Vickers' hardness apart from the dark position of surperficial 50 μ m of the grind section that comprises groove portion 1a is more than 740 (Rockwell C hardness is 62), therefore, while using spot contact bearing 10 in the lubricating oil that is mixed with impurity, can reduce the size of the impression generating while nipping above-mentioned impurity.In addition, in inner ring 1, the Vickers' hardness apart from the dark position of surperficial 50 μ m of the grind section that comprises groove portion 1a is below 900 (Rockwell C hardness is 67), therefore can prevent embrittlement.

In addition, be following measured value apart from the Vickers' hardness of the dark position of surperficial 50 μ m, that is, cut off above-mentioned outer ring 2 and above-mentioned inner ring 1 along depth direction from surface after, apart from the above-mentioned surperficial 50 dark positions of μ m, be pressed into Vickers pressure head and the value measured.In addition, Rockwell C hardness is by measured Vickers' hardness being converted to the value of trying to achieve.

Outside the grind section that comprises groove portion 2a, 1a of inner ring 2,1 and ball 3 separately from surface to the upper layer of the scope of 10 μ m, have the particle being formed by vanadium nitride and/or the particle being formed by vanadium carbonitride.The particle diameter of above-mentioned particle, from by the dispersion-strengthened viewpoint that improves yielding stress based on Ao Luowan mechanism, is more than 0.2 μ m, from bring out the viewpoint of particle coarsening by Ostwald ripening, is preferably below 2 μ m.In addition, grind section from surface to the upper layer of the scope of 10 μ m, also contain the particle of particle diameter less than 0.2 μ m.

In addition, on the grind section that comprises groove portion 2a, 1a of inner ring 2,1 and ball 3 surface separately, cementite and M have been separated out outside ₇c ₃type carbide and M ₂₃c ₆type carbide.

Outer inner ring 2, 1 comprise groove portion 2a, the grind section of 1a and ball 3 separately from surface to the area occupation ratio of the particle of the particle of particle diameter 0.2～2 μ m being formed by above-mentioned vanadium nitride of the upper layer of the scope of 10 μ m and/or particle diameter 0.2～2 μ m that formed by vanadium carbonitride, from by improving yielding stress based on Ao Luowan mechanism dispersion-strengthened at fixed ring and drive the each circle of circle to guarantee the viewpoint of sufficient static load ability, be more than 1%, from by suppressing excessive nitrogen to infiltrating steel and guaranteeing required carbon amount, and the Rockwell C hardness (or Vickers' hardness) of the dark position apart from above-mentioned surperficial 50 μ m is made with fixed ring and driven the corresponding prescribed value of the each circle of circle, and at fixed ring and drive circle to guarantee that the viewpoint of sufficient static load ability sets out on each circle, be below 10%.In addition, in this manual, the area occupation ratio of above-mentioned particle refers to, the area occupation ratio of the particle that the particle of the particle of the particle diameter being made up of vanadium nitride 0.2～2 μ m the upper layer of the scope from surface to 10 μ m and particle diameter 0.2～2 μ m being made up of vanadium carbonitride is added together.

Outer inner ring 2, 1 comprise groove portion 2a, the grind section of 1a and ball 3 separately from surface to the content of the carbon of the upper layer of the scope of 10 μ m, from making and fixed ring and drive the corresponding prescribed value of the each circle of circle having to the remained austenite content of the alleviation effects of the stress concentration of the surface damage portions such as impression, and make with fixed ring and drive the viewpoint of the surface hardness of the corresponding regulation of the each circle of circle to set out, be more than 1.1 quality %, from the thick precipitate by reducing the carbide above-mentioned upper layer (for example, particle diameter exceedes the precipitate of 10 μ m) amount, further improving the viewpoint in life-span sets out, be below 1.6 quality %.

Outer inner ring 2, 1 comprise groove portion 2a, the content of the nitrogen the upper layer of the grind section of 1a and ball 3 scope from surface to 10 μ m separately, from by the dispersion-strengthened yielding stress that improves based on Ao Luowan mechanism, thereby the viewpoint of guaranteeing sufficient static load ability is set out, be more than 0.1 quality %, from by suppressing excessive nitrogen to infiltrating steel and guaranteeing required carbon amount, Vickers' hardness (or Rockwell C hardness) apart from the dark position of surperficial 50 μ m and remained austenite content are made with fixed ring and driven the corresponding prescribed value of the each circle of circle, and realize long lifetime, and at fixed ring and drive circle to guarantee that the viewpoint of sufficient static load ability sets out on each circle, be below 1.0 quality %.

Rolling body is the common rolling body that ball 3 also can form for the parts that are made up of JIS SUJ2.In addition, ball 3 also can be made up of the bearing component parts same with outer ring 2.

In addition, in the spot contact bearing 10 of the second embodiment, outer ring 2 is fixed ring, and inner ring 1 encloses for driving, but in the present invention, can be also that inner ring 1 is fixed ring, and outer ring 2 is for driving circle.In this situation, be inner ring 1 as fixed ring, about grind section, use following bearing component parts, , content from surface to the carbon of the upper layer of the scope of 10 μ m is 1.1～1.6 quality %, Vickers' hardness apart from the dark position of surperficial 50 μ m is 800～940 (Rockwell C hardness is 64～68), remained austenite content apart from the dark position of surperficial 10 μ m is 5～30 volume %, the content of the nitrogen the upper layer of the scope from above-mentioned surface to 10 μ m is 0.1～1.0 quality %, the particle of particle diameter 0.2～2 μ m that there is the particle of particle diameter 0.2～2 μ m being formed by vanadium nitride and/or formed by vanadium carbonitride the upper layer of the scope from above-mentioned surface to 10 μ m, and the area occupation ratio of the particle of the particle of particle diameter 0.2～2 μ m being made up of above-mentioned vanadium nitride the upper layer of the scope from above-mentioned surface to 10 μ m and/or particle diameter 0.2～2 μ m being made up of vanadium carbonitride is 1～10%.

In addition, outer ring 2 can be manufactured by the manufacture method of the bearing component parts of second embodiment of the invention described later.

In addition, inner ring 1 for example obtains by following operation,, the steel of the vanadium of the chromium that contains 3.2～5.0 quality % and 0.05 quality % is above and less than 0.5 quality % are processed into the moulding starting material that regulation shape obtains, and are in the carbonitriding atmosphere of 2～5 volume % at carbon potential 0.9～1.3 and ammonia concentration, and these moulding starting material are heated to 850～900 ℃, carry out chilling, then obtained intermediate raw material is implemented to be heated to 160 ℃ of above temper, thereafter, implement precision work.

(manufacture method of bearing component parts)

Then,, as the example of the manufacture method of above-mentioned bearing component parts, the manufacture method of outer ring is described.Fig. 2 B is the process picture sheet of the manufacture method of the bearing component parts (outer ring) of second embodiment of the invention.

First, manufacture by the chromium that contains 3.2～5.0 quality %, the ring-type starting material 63 (with reference to Fig. 2 B (a)) of the outer ring that the steel of the vanadium of and less than 0.5 quality % above with 0.05 quality % form, obtained ring-type starting material 63 are implemented to machining etc., be processed into regulation shape, obtain the moulding starting material 64 (" front manufacturing procedure " of outer ring as described below, with reference to Fig. 2 B (b)), the moulding starting material 64 of described outer ring are forming roller surface 61a, end face 61b, the part that shoulder face 61c and periphery 61d are each has grind, and there is the chamfering 61e of the outer circumferential side of the outer ring of the cross section R shape of not grinding being connected with end face 61b and periphery 61d, the chamfering 61f of the inner circumferential side of the outer ring of the cross section rectilinear form not grinding being connected with end face 61b and shoulder face 61c.

According to this steel, the amount of the thick eutectic carbides of separating out when the surperficial manufacture of outer ring 61 reduces, and can suppress the fatigure failure in bearing, and after quenching and after carbonitriding and tempering, can guarantee sufficient hardness.

In above-mentioned steel, carbon is the element of the following effect of performance, that is, in the time carrying out the carbonitriding treatment process of next procedure, make the hardness of steel increase, and obtains the inside hardness for guaranteeing intensity.In addition, carbon is the element of the following effect of performance,, processes the carbide of front remaining a large amount of not solid solution in steel by being formed in carbonitriding described later that is, and the also state of the carbide of remaining fine and a large amount of not solid solution after carbonitriding is processed, can improve rolling fatigue life.

The content of contained carbon in above-mentioned steel, from the remaining not viewpoint of the carbide of solid solution fully steel, be more than 0.7 quality %, from obtaining fully carbonitriding processibility before treatment, and the viewpoint that suppresses the generation of the thick eutectic carbides that easily becomes fatigure failure starting point in the time manufacturing steel is set out, and is below 0.9 quality %.

In addition, in above-mentioned steel, chromium is the element of the following effect of performance,, by in the carbonitriding stage before treatment, when being created on carbonitriding and processing, as the carbide of separating out a large amount of not solid solution that core plays a role, and separate out fine carbide (M on surperficial carbonitrided case after carbonitriding ₇c ₃type carbide, M ₂₃c ₆type carbide), fine carbonitride (M ₇(C, N) ₃type carbonitride, M ₂₃(C, N) ₆type carbonitride) and fine nitride (CrN, VN), improve the rolling fatigue life of bearing component parts, and improve the resistivity of the temper softening to temper operation described later.In addition, chromium carries out carbonitride in steel and the generation of nitride promotes the promotion of the nitrogenizing reaction of the steel most surface layer causing, and carries out the inhibition (inhibition of the generation of over cargurization tissue) of carburization reaction.

From the viewpoint for obtaining above-mentioned effect, in steel, the content of contained chromium is more than 3.2 quality %, from easily becoming the viewpoint of inhibition of generation of eutectic carbides of fatigure failure starting point and the viewpoint reducing costs, is below 5.0 quality %.

In above-mentioned steel, vanadium is the element very strong with the avidity of carbon, is the element that forms carbide.In addition, the vanadium carbide being generated by carbon and vanadium, compared with molybdenum carbide, solid solubility temperature is high, therefore in the temperature range of the carbonitriding processing in the time of the manufacture of bearing component parts of the present invention, the scarcely solid solution of vanadium carbide existing before carbonitriding is processed, is present in steel as the vanadium carbide of not solid solution.Carbide (VC) when the vanadium carbide of this not solid solution is processed as carbonitriding, carbonitride (V (C,) and nitride ((Cr N), V) N) etc. the core of separating out play a role, and contribute to the miniaturization of the precipitates such as above-mentioned carbide, carbonitride, nitride, can improve hardness and the rolling fatigue life of steel.And vanadium is not second to the chromium in steel, the generation that can carry out carbonitride and nitride promotes the promotion of nitrogenizing reaction and the inhibition of carburization reaction (inhibition of the generation of over cargurization tissue) of the steel most surface layer causing.In addition, vanadium as the resistivity for improving the temper softening that temper operation described later is caused element play a role.From the viewpoint for obtaining above-mentioned effect, in steel, the content of contained vanadium is more than 0.05 quality %, from fully guaranteeing solid solution carbon amount and guarantee as fixed ring to be the viewpoint of the sufficient remained austenite content in outer ring by the generation that suppresses vanadium carbide, be less than 0.5 quality %.

In above-mentioned steel, silicon is the necessary element of deoxidation during for the refining of steel.In addition, silicon has and is difficult to solid solution in the character of carbide, and therefore silicon is the element with the effect of the thick growth that suppresses carbide.

From obtaining the viewpoint of above-mentioned effect, in steel, the content of contained silicon is more than 0.05 quality %, from guarantee the viewpoint of the required cost such as sufficient processibility and reduction steel and processing carbonitriding is processed, is below 0.70 quality %.

From obtaining the viewpoint of above-mentioned effect, in steel, the content of contained manganese is more than 0.05 quality %, thereby increase and make Carbide Precipitation improve the hardness of steel and obtain the viewpoint of sufficient hot workability and machinability from the amount of the carbide that makes the not solid solution steel, be below 0.7 quality %, be preferably below 0.50 quality %.

In above-mentioned steel, molybdenum is the element stronger than chromium with the avidity of carbon, is the element relevant to the generation of carbide and carbonitride.In addition, molybdenum is that carbide in the temperature of the carbonitriding processing while making to manufacture bearing component parts of the present invention and the solid solubility temperature of carbonitride rise, and makes the carbide of not solid solution and the element that carbonitride increases.Therefore, molybdenum is that fine carbide amount and the carbonitride amount for making carbonitriding surperficial carbonitrided case after treatment increases, and the important element that makes the hardness of steel increase.In addition, molybdenum improves the hardenability of steel, and the remained austenite content in steel is increased.In addition, molybdenum is to make carbide (M ₂₃c ₆type carbide) and carbonitride (M ₂₃(C, N) ₆type carbonitride) element of separating out efficiently.

From obtaining the viewpoint of above-mentioned effect, in steel, the content of contained molybdenum is more than 0.10 quality %, from the viewpoint reducing costs and the viewpoint that suppresses the generation of the thick eutectic carbides that becomes fatigure failure starting point, is below 1.0 quality %.

Then, be in the carbonitriding atmosphere of 2～5 volume % at carbon potential 0.9～1.3 and ammonia concentration, the moulding starting material 64 (intermediate raw material) of obtained outer ring are heated to 850～900 ℃ and keep the specified time, thereafter, be quenched to specified temperature (" carbonitriding treatment process ", with reference to Fig. 2 B (c)).

Carbon potential in carbonitriding atmosphere, from surperficial hardness being made to the viewpoint of sufficient hardness, be more than 0.9, from the area occupation ratio of the precipitate that comprises above-mentioned vanadium nitride or vanadium carbonitride being made to above-mentioned scope and being suppressed the viewpoint of the generation of over cargurization tissue, be below 1.3.

In addition, ammonia concentration in carbonitriding atmosphere, from suppress the generation of over cargurization tissue and the resistivity of the temper softening that raising causes temper operation described later viewpoint, be more than 2 volume %, from preventing the viewpoint of the embrittlement that excessive nitrogenize causes, be below 5 volume %.

Heating in carbonitriding atmosphere keeps temperature, from forming the viewpoint of sufficient hardened layer, be more than 850 ℃, the viewpoint that suppresses the generation of over cargurization tissue to infiltrating bearing component parts and suppress thick Carbide Precipitation from suppressing excessive carbon, is below 900 ℃.

Chilling is undertaken by the oil cooling in the oil bath of cooling oil.Conventionally, the oil bath temperature of cooling oil is 60～180 ℃.

Then, the moulding starting material 64 (intermediate raw material) of carbonitriding outer ring after treatment are cooled to the deepfreeze (" deepfreeze ", with reference to Fig. 2 B (d)) of the specified temperature of 0 ℃ of less than.

Cooling temperature in deepfreeze, from the viewpoint reducing costs, is preferably more than-100 ℃, from residual austenite being become to the martensitic viewpoint of regulation, is preferably below-50 ℃.

In addition, the cooling time in deepfreeze, from the viewpoint in order to guarantee sufficient static load ability as fixed ring, be preferably more than 1 hour.

By carrying out deepfreeze like this, residual austenite is become to martensite, can be in order to guarantee sufficient static load ability as fixed ring.

Then, the moulding starting material 64 (intermediate raw material) of the outer ring after above-mentioned deepfreeze are heated to specified temperature and the temper (" temper operation ", with reference to Fig. 2 B (e)) that keeps.

Heating in temper keeps temperature, from guaranteeing the stable on heating viewpoint as bearing, is more than 150 ℃, from guaranteeing the viewpoint of regulation hardness, is below 250 ℃.

In addition, the heating hold-time in temper, from the viewpoint of processing equably, is more than 0.5 hour.

Thereafter, the part that formation roller surface 61a, the end face 61b of the moulding starting material 64 (intermediate raw material) to the outer ring after temper operation, shoulder face 61c, periphery 61d are each, the processing of enforcement fine grinding, and roller surface 61a is implemented to superfinishing, be finish-machined to specified accuracy (with reference to Fig. 2 B (f), " finishing step ").Can obtain like this target outer ring 61.In obtained outer ring 61, roller surface 61a, end face 61b, shoulder face 61c and periphery 61d form as grind section, in this outer ring 61, the chamfering 61f of the chamfering 61e of the outer circumferential side of outer ring and the inner circumferential side of outer ring forms as the non-grind section of not grinding.

Embodiment

, utilize embodiment to be further elaborated to the present invention below, but the present invention is not limited to this embodiment.

(embodiment 1-1～1-3 and comparative example 1-1～1-7)

Use respectively two kinds of steel A and the B with the composition shown in table 1, be processed into regulation shape, be manufactured on the part that forms roller surface and have spot contact bearing (model 6206) the Internal and external cycle moulding starting material separately of grind.The steel B of table 1 is the JIS SUJ2 as bearing steel.In addition, the diameter of rolling body is 9.525mm.

[table 1]

Then, to obtained moulding starting material, under the heat-treat condition shown in Fig. 3～Figure 12, implement thermal treatment, the part of the above-mentioned roller surface of formation to the intermediate raw material after obtained thermal treatment is implemented attrition process, manufactures the combination of the Internal and external cycle of embodiment 1-1～1-3 and comparative example 1-1～1-7.Particularly, in the combination of embodiment 1-1～1-3 and comparative example 1-1～1-7 Internal and external cycle separately, in each embodiment and comparative example, as shown in table 3 and 5, inner ring and outer ring are the combination of mutually the same steel being implemented to the Internal and external cycle that the thermal treatment of identical heat-treat condition obtains.

Heat-treat condition shown in Fig. 3 is, by moulding starting material be 1.1 at carbon potential, ammonia concentration is in the carbonitriding atmosphere of 2 volume %, after heating 7 hours at 860 ℃, oil cooling to 80 ℃,,, at 180 ℃, heat 2 hours (temper) (experiment numbers 1-1) thereafter.

Heat-treat condition shown in Fig. 4 is, by moulding starting material be 1.2 at carbon potential, ammonia concentration is in the carbonitriding atmosphere of 5 volume %, after heating 7 hours at 860 ℃, oil cooling to 80 ℃,,, at 180 ℃, heat 2 hours (temper) (experiment numbers 1-2) thereafter.

Heat-treat condition shown in Fig. 5 is, to in the carbonitriding atmosphere that moulding starting material are 1.0 at carbon potential, ammonia concentration is 2 volume %, at 860 ℃, heat after 7 hours, oil cooling to 80 ℃ thereafter, heats 2 hours (temper) (experiment numbers 1-3) at 180 ℃.

Heat-treat condition shown in Fig. 6 is, in the atmosphere that is 0.8 at carbon potential by moulding starting material, at 830 ℃, heat 0.5 hour, carried out after integral quenching oil cooling to 80 ℃,,, at 180 ℃, heat 2 hours (temper) (experiment numbers 1-4) thereafter.

Heat-treat condition shown in Fig. 7 is that, after heating 5 hours at 850 ℃ in the carbonitriding atmosphere that is 1.2 at carbon potential by moulding starting material, oil cooling to 80 ℃ thereafter, heats 2 hours (temper) (experiment numbers 1-5) at 160 ℃.

Heat-treat condition shown in Fig. 8 is, to in the carbonitriding atmosphere that moulding starting material are 1.2 at carbon potential, ammonia concentration is 2 volume %, at 850 ℃, heat after 4 hours, oil cooling to 80 ℃ thereafter, heats 2 hours (temper) (experiment numbers 1-6) at 160 ℃.

Heat-treat condition shown in Fig. 9 is, in the atmosphere that is 0.8 at carbon potential by moulding starting material, at 900 ℃, heat 0.5 hour, carried out after integral quenching oil cooling to 80 ℃,,, at 180 ℃, heat 2 hours (temper) (experiment numbers 1-7) thereafter.

Heat-treat condition shown in Figure 10 is that, after heating 7 hours at 900 ℃ in the carbonitriding atmosphere that is 1.2 at carbon potential by moulding starting material, oil cooling to 80 ℃ thereafter, heats 2 hours (temper) (experiment numbers 1-8) at 160 ℃.

Heat-treat condition shown in Figure 11 is, to in the carbonitriding atmosphere that moulding starting material are 1.2 at carbon potential, ammonia concentration is 1 volume %, at 860 ℃, heat after 7 hours, oil cooling to 80 ℃ thereafter, heats 2 hours (temper) (experiment numbers 1-9) at 180 ℃.

Heat-treat condition shown in Figure 12 is, to in the carbonitriding atmosphere that moulding starting material are 1.2 at carbon potential, ammonia concentration is 15 volume %, at 860 ℃, heat after 7 hours, oil cooling to 80 ℃ thereafter, heats 2 hours (temper) (experiment numbers 1-10) at 180 ℃.

(test example 1-1)

About embodiment 1-1～1-3, the inner ring of comparative example 1-1～1-7, to the Vickers' hardness (Rockwell C hardness) apart from the dark position of surface (grind section) 50 μ m of groove portion, apart from the skin section remained austenite content of the dark position of above-mentioned surperficial 10 μ m, apart from the inside remained austenite content of the dark position of above-mentioned surperficial 2mm, carbon content the upper layer of the scope from above-mentioned surface to 10 μ m, nitrogen content the upper layer of the scope from above-mentioned surface to 10 μ m, precipitate form, and vanadium the upper layer of scope from above-mentioned surface to 10 μ m is that the area occupation ratio of precipitate (particle of the particle of particle diameter 0.2～2 μ m being made up of vanadium carbonitride and particle diameter 0.2～2 μ m being made up of vanadium nitride) is studied.

In order to measure the hardness of upper layer of essence, after above-mentioned inner ring is cut off along depth direction from the surface of groove portion, be pressed into Vickers pressure head apart from the above-mentioned surperficial 50 dark positions of μ m and measuring the Vickers' hardness of the position dark apart from above-mentioned surperficial 50 μ m.In addition, Rockwell C hardness is by converting measured Vickers' hardness to try to achieve.The degree of depth from surface to 10 μ m by the groove portion to above-mentioned inner ring is carried out electrolytic polishing, and measures the surperficial remained austenite content after electrolytic polishing, tries to achieve the skin section remained austenite content of the position dark apart from above-mentioned surperficial 10 μ m.The degree of depth from surface to 2mm by the groove portion to above-mentioned inner ring is carried out electrolytic polishing, and measures the surperficial remained austenite content after electrolytic polishing, tries to achieve the inside remained austenite content of the position dark apart from above-mentioned surperficial 2mm.The carbon content of the scope from above-mentioned surface to 10 μ m and from surface to the nitrogen content of the scope of 10 μ m, by after above-mentioned inner ring is cut off along depth direction from the surface of groove portion, measures each content of the scope from above-mentioned surface to 10 μ m and tries to achieve respectively.

Above-mentioned precipitate form, after above-mentioned inner ring is cut off along depth direction from the surface of groove portion, observes and evaluates to the scope of 10 μ m from above-mentioned surface.Vanadium the upper layer of the scope from above-mentioned surface to 10 μ m is the area occupation ratio of precipitate (particle of the particle of particle diameter 0.2～2 μ m being made up of vanadium carbonitride and particle diameter 0.2～2 μ m being made up of vanadium nitride), after above-mentioned inner ring is cut off along depth direction from surface, in the scope from above-mentioned surface to 10 μ m, measure.

In addition, above-mentioned precipitate form and vanadium are the area occupation ratio of precipitate (particle of the particle of particle diameter 0.2～2 μ m being made up of vanadium carbonitride and particle diameter 0.2～2 μ m being made up of vanadium nitride), at 800 μ m ²mensuration visual field in, acceleration voltage: 15.0kV, irradiate electric current: 2.016 × 10 ^-7a and scanning multiplying power: under the condition of 3000 times, utilize field emission type electron probe microanalyzer, carbon (Figure 13 (a)), nitrogen (Figure 13 (b)) and vanadium (Figure 13 (c)) are made to reflection, utilize image processing apparatus to calculate area occupation ratio.Figure 13 (a)～(c) result of reflection is made carbon, nitrogen and the vanadium on the surface of the inner ring of embodiment 1-1 (from surface to the scope of 10 μ m) respectively in expression.In Figure 13, graduated scale represents 5 μ m.

From the result shown in Figure 13 (a)～(c), in the scope from surface to 10 μ m of the groove portion of the inner ring of embodiment 1-1, can confirm by the particle diameter more than dispersion-strengthened 0.2 μ m that can improve yielding stress based on Ao Luowan mechanism and what can bring out particle diameter below 2 μ m of particle coarsening by Ostwald ripening is the particle that precipitate (vanadium carbonitride and vanadium nitride) forms by vanadium.In addition, from the result shown in Figure 13 (a)～(c), also have less than 0.2 μ m particle diameter be the particle that precipitate forms by vanadium.

In addition, similarly, about embodiment 1-2～1-3, the inner ring of comparative example 1-6 and the each example of 1-7, the result that the area occupation ratio that is precipitate (particle of the particle of particle diameter 0.2～2 μ m being made up of vanadium carbonitride and particle diameter 0.2～2 μ m being made up of vanadium nitride) to the vanadium the upper layer of above-mentioned precipitate form and the scope from above-mentioned surface to 10 μ m has carried out evaluating is, at embodiment 1-2～1-3, the surface (scope from surface to 10 μ m) of the inner ring of comparative example 1-6 and the each example of 1-7, also exist by vanadium is the particle of particle diameter 0.2～2 μ m of precipitate (vanadium nitride and vanadium carbonitride) formation, the surface (from surface to the scope of 10 μ m) of the groove portion of the inner ring of embodiment 1-2～1-3, comparative example 1-6 and the each example of 1-7 be the size of particle and the shape of particle that precipitate (vanadium nitride and vanadium carbonitride) forms by vanadium, with the inner ring of embodiment 1-1 be that the particle that precipitate forms does not have larger difference by vanadium.But what separated out on the surface (from surface to the scope of 10 μ m) of the groove portion of the inner ring of embodiment 1-2～1-3, comparative example 1-6 and the each example of 1-7 is that the amount (area occupation ratio) of particle of particle diameter 0.2～2 μ m that forms of precipitate (vanadium nitride and vanadium carbonitride) is different from embodiment 1-1 by vanadium.

In addition, utilize the combination of the Internal and external cycle of embodiment 1-1～1-3, comparative example 1-1～1-7, be assembled into respectively each spot contact bearing of embodiment 1-1～1-3, comparative example 1-1～1-7.In the spot contact bearing of embodiment 1-1～1-3 and the each example of comparative example 1-2～1-7, as rolling body, use steel B is implemented to the thermal treatment of the heat-treat condition shown in Fig. 8 and the rolling body that obtains.On the other hand, in comparative example 1-1, as rolling body, use steel B is implemented to the thermal treatment of the heat-treat condition shown in Fig. 6 and the rolling body that obtains.

The rated capacity of each spot contact bearing of embodiment 1-1～1-3, comparative example 1-1～1-7 is than being 1.3C ₀.About each spot contact bearing of embodiment 1-1～1-3, comparative example 1-1～1-7, the life-span (life-span in impurity oil) the life-span index being mixed with in the lubricating oil of impurity is studied.In addition, about each spot contact bearing of embodiment 1-1～1-3, comparative example 1-1～1-7, be that raceway circle depth of indentation, dimensional stability are studied to static load ability index.

About the life-span in impurity oil, under the conditions shown in Table 2, test.About the life-span in above-mentioned impurity oil, use judgment standard below to evaluate.

(judgment standard)

Zero: the more than 8 times of the L10 life-span of the spot contact bearing of comparative example 1-1.

×: 8 times of the L10 life-span of the spot contact bearing of not enough comparative example 1-1.

[table 2]

	Test conditions
		Test specimen bearing designation	6202 (internal diameter 30mm, external diameter 62mm, width 16mm)
Load	Fr=9kN/ group (0.46Cr)
		Rotating speed	2500rpm
Lubricated	Turbine oil #68 (90 ℃ of oil baths)
		Impurity	Rapid steel (0.02 quality %, particle diameter 100～150 μ m, hardness 730Hv)
Failure number	2

In addition, raceway circle depth of indentation as shown in figure 14, evaluate by following operation,, by chimeric to inner ring and the axle of the spot contact bearing of embodiment 1-1～1-3, comparative example 1-1～1-7, and axis is set as to level, a ball is configured in to the top of the vertical of inner ring raceway face, the periphery that is the vertical the top of outer ring from the vertical top of this ball applies the load of 14.7kN, is determined at the depth of indentation that produces the part of ultimate load in the raceway circle of above-mentioned spot contact bearing with three-dimensional measuring instrument.Raceway circle depth of indentation is the value of the summation of the depth of indentation producing at inner ring and the depth of indentation producing in outer ring.About above-mentioned raceway circle depth of indentation, use judgment standard below to evaluate.

(judgment standard)

Zero: the degree of depth of impression is below 0.635 μ m

×: the degree of depth of impression is greater than 0.635 μ m

In addition, above-mentioned " 0.635 μ m " is that conduct in the spot contact bearing of rolling body diameter while being 9.525mm does not hinder the set deformation volume of the limit of smooth and easy rotation.This value is following value,, suppose in the tolerable limit of the distortion causing at the impression of the rolling bearing entirety with rolling body diameter (9.525mm) × 1/10000 judgement, distortion that impression causes respectively equably (respectively account for entirety 1/3) results from inner ring, outer ring and rolling body, the value that depth of indentation of inner ring and the depth of indentation of outer ring are added together be the distortion that causes of the impression of rolling bearing entirety tolerable limit 2/3,2/3 value of obtaining as permissible value of the tolerable limit of the distortion therefore impression of rolling bearing entirety being formed.

Axle (external diameter 30mm, length 50mm) is pressed in the inner ring of product innovation of embodiment 1-1～1-3, comparative example 1-1～1-7, in thermostatic bath, at 150 ℃, keeps 1000 hours.In addition, the fashionable tensile stress of axial compression is 100～150MPa., axle from each inner ring unloaded, measure the internal diameter of 6 points (axially 2 points spaced apart at equally spaced three positions spaced apart in the circumferential direction) of the aperture surface of each inner ring thereafter.In addition, in contrast, measure the internal diameter of above-mentioned 6 before axial compression enters.,, calculate the velocity of variation (size changing rate (%)) of the size of above-mentioned 6 of size after the each time inner ring aperture surface before keeping with respect to heating thereafter.In addition, size changing rate is (internal diameter size before the internal diameter size-axial compression after the each time enters) internal diameter size before/axial compression enters.

About above-mentioned size changing rate, use judgment standard below to evaluate.

Zero: size changing rate less than 0.11%

×: size changing rate is more than 0.11%

Table 3 represents kind, the heat-treat condition of the steel of the assembling of spot contact bearing of kind, heat-treat condition, the formation embodiment 1-1～1-3 of the Internal and external cycle of embodiment 1-1～1-3 steel used rolling body used.In addition, table 4 represents kind, the heat-treat condition of the steel of the assembling of spot contact bearing of kind, heat-treat condition, the formation comparative example 1-1～1-7 of the Internal and external cycle of comparative example 1-1～1-7 steel used rolling body used.With respect to the combination of the Internal and external cycle of embodiment 1-1～1-3, comparative example 1-2～1-7, as rolling body, use steel B, and use by implement the rolling body that thermal treatment obtains under the heat-treat condition shown in Fig. 8.With respect to the combination of the Internal and external cycle of comparative example 1-1, as rolling body, use steel B, and use by implement the rolling body that thermal treatment obtains under the heat-treat condition shown in Fig. 6.

[table 3]

[table 4]

Table 5 (embodiment 1-1～1-3) and table 6 (comparative example 1-1～1-7) represent embodiment 1-1～1-3, the Vickers' hardness (Rockwell C hardness) apart from the dark position of surperficial 50 μ m of the groove portion of the inner ring of comparative example 1-1～1-7, apart from the skin section remained austenite content of the dark position of above-mentioned surperficial 10 μ m, apart from the inside remained austenite content of the dark position of above-mentioned surperficial 2mm, carbon content the upper layer of the scope from above-mentioned surface to 10 μ m, nitrogen content the upper layer of the scope from above-mentioned surface to 10 μ m, precipitate form, vanadium the upper layer of the scope from surface to 10 μ m is the area occupation ratio of precipitate, embodiment 1-1～1-3, life-span in the impurity oil of the spot contact bearing of comparative example 1-1～1-7, embodiment 1-1～1-3, the raceway circle depth of indentation of the spot contact bearing of comparative example 1-1～1-7 and embodiment 1-1～1-3, the result that the dimensional stability of the inner ring of comparative example 1-1～1-7 is studied.In table, " Vickers' hardness (Rockwell C hardness) " represents the Vickers' hardness apart from the dark position of surperficial 50 μ m (or Rockwell C hardness) of groove portion; " skin section remained austenite content (volume %) " represents the skin section remained austenite content apart from the dark position of surperficial 10 μ m of groove portion; " carbon content (quality %) " and " nitrogen content (quality %) " represents respectively carbon content and the nitrogen content the upper layer of the scope from surface to 10 μ m of groove portion; The area occupation ratio of the particle that the particle of the particle of the particle diameter being made up of vanadium nitride 0.2～2 μ m the upper layer of the scope from surface to 10 μ m of " vanadium is the area occupation ratio (%) of precipitate " expression groove portion and particle diameter 0.2～2 μ m being made up of vanadium carbonitride is added together.In addition, " inner remained austenite content (volume %) " represents that ratio is from the darker region of the carbonitrided case of the surface formation of the Internal and external cycle of embodiment 1-1～1-3, comparative example 1-3,1-6,1-7, than the remained austenite content apart from the darker region of the surperficial 1.5mm of groove portion,, represent apart from the dark inside remained austenite content of the surperficial 2mm of groove portion.

About comparative example 1-1,1-2,1-4,1-5 too, " inner remained austenite content (volume %) " represent inner ring groove portion apart from the dark inside remained austenite content of surperficial 2mm.The degree of depth of the surperficial 2mm of distance is the darker region of cementation zone that the ratio of the inner ring of comparative example 1-2,1-5 forms from surface.

Result is as shown in Table 5 known, and in the impurity oil of the spot contact bearing of embodiment 1-1～1-3, the life-span is the more than 8 times of L10 life-span of the spot contact bearing of comparative example 1-1.Therefore, known, according to the Internal and external cycle of embodiment 1-1～1-3, can realize the long lifetime of rolling bearing.

In addition, result is as shown in Table 5 known, and the raceway circle depth of indentation of the spot contact bearing of embodiment 1-1～1-3 is below the 0.635 μ m of the limit set deformation volume that does not hinder smooth and easy rotation of the spot contact bearing while being 9.525mm as rolling body diameter.Therefore, known, according to the Internal and external cycle of embodiment 1-1～1-3 and rolling body, can guarantee sufficient static load ability.

In addition, result is as shown in Table 5 known, the size changing rate less than 0.11% (0.05～0.06%) of the inner ring of 1000 hours later embodiment 1-1～1-3 from axial compression enters, compared with the inner ring of comparative example 1-1, the excellent in dimensional stability of the inner ring of embodiment 1-1～1-3.

On the other hand, result is as shown in Table 6 known, in the impurity oil of the spot contact bearing of comparative example 1-2～1-4 8 times (1～3 times) in the L10 life-span of the spot contact bearing of not enough comparative example 1-1 of life-span, compared with the spot contact bearing of embodiment 1-1～1-3, lifetime in impurity oil.In addition, known, the raceway circle depth of indentation of the spot contact bearing of comparative example 1-1～1-4 is greater than 0.635 μ m (0.82～1.0 μ m), for the limit that does not hinder smooth and easy rotation of spot contact bearing is more than set deformation volume.In addition, known, the size changing rate of the inner ring of comparative example 1-1～1-4 is 0.11～0.20%, and dimensional stability is low.

In addition, result is as shown in Table 6 known, in the impurity oil of the spot contact bearing of comparative example 1-5 and 1-6, the life-span is 8 times of the L10 life-span above (being respectively 10 times (comparative example 1-5) and 12 times (comparative example 1-6)) of the spot contact bearing of comparative example 1-1, is roughly equal to the life-span in the impurity oil of the spot contact bearing of embodiment 1-1～1-3.

But, the raceway circle depth of indentation of the spot contact bearing of comparative example 1-5 and 1-6 is than 0.635 μ m large (being respectively 1.4 μ m (comparative example 1-5) and 1.6 μ m (comparative example 1-6)), for the limit that does not hinder smooth and easy rotation of spot contact bearing is more than set deformation volume.In addition, known, the size changing rate of the inner ring of comparative example 1-5 is respectively 0.15%, and dimensional stability is low.

In addition we know, the size changing rate of the inner ring of comparative example 1-6 is 0.06%, is roughly equal to the inner ring of embodiment 1-1～1-3.

In addition, result is as shown in Table 6 known, and the size changing rate of the inner ring of comparative example 1-7 is 0.05%, is roughly equal to the inner ring of embodiment 1-1～1-3.

But, in the impurity oil of the spot contact bearing of comparative example 1-7 8 times (3 times) in the L10 life-span of the spot contact bearing of not enough comparative example 1-1 of life-span, compared with the spot contact bearing of embodiment 1-1～1-3, lifetime in impurity oil.And the raceway circle depth of indentation of the spot contact bearing of comparative example 1-7 is larger (2.0 μ m), for the limit that does not hinder smooth and easy rotation of spot contact bearing is more than set deformation volume than 0.635 μ m.

Therefore, from these results, use steel A, in Internal and external cycle, Vickers' hardness in the dark position of the surperficial 50 μ m of distance is in the scope of 740～900 (Rockwell C hardness is 62～67), remained austenite content apart from the dark position of surperficial 10 μ m is in the scope of 20～55 volume %, carbon content the upper layer of the scope from surface to 10 μ m is in the scope of 1.1～1.6 quality %, nitrogen content the upper layer of the scope from surface to 10 μ m is in the scope of 0.1～1.0 quality %, and in the situation in the scope that the area occupation ratio that is the particle of particle diameter 0.2～2 μ m that forms of precipitate by vanadium the upper layer of the scope from surface to 10 μ m is 1～10% (embodiment 1-1～1-3), can realize the long lifetime of rolling bearing, can guarantee sufficient static load ability and sufficient dimensional stability.

On the other hand, known, in Internal and external cycle, in the Vickers' hardness (Rockwell C hardness) apart from the dark position of surperficial 50 μ m, be not included in above-mentioned scope apart from the particle that is particle diameter 0.2～2 μ m that forms of precipitate by vanadium the upper layer of the nitrogen content the upper layer of the carbon content the upper layer of the remained austenite content of the dark position of surperficial 10 μ m, scope from surface to 10 μ m, scope from surface to 10 μ m and the scope from surface to 10 μ m, life-span, static load ability and the dimensional stability of rolling bearing are all insufficient.

(test example 1-2)

Utilize the spot contact bearing of the product innovation of embodiment 1-1, under the conditions shown in Table 2, measure until produce the time (test period) of surface damage, the relation of research trial time and cumulative damage probability on constituent part.In addition, except using the situation of spot contact bearing of comparative example 1-1 and 1-3, carry out operation similar to the above, the relation of test period and cumulative damage probability is studied.By the coordinate graph of relation that represents test period and cumulative damage probability in Figure 15.In figure, solid line (filled circles) represents the spot contact bearing of embodiment 1-1; Long and short dash line (hollow tetragon) represents the spot contact bearing of comparative example 1-1; Two dot chain line (hollow triangle) represents the spot contact bearing of comparative example 1-3.

Result is as shown in Figure 15 known, compared with the spot contact bearing of the spot contact bearing of embodiment 1-1 and comparative example 1-1 and 1-3, life roughly 7～10 times.

(test example 1-3)

Axle (external diameter 30mm, length 50mm) is pressed in the inner ring of part of embodiment 1-1, in thermostatic bath, at 150 ℃, keeps the aging time of regulation.In addition, the fashionable tensile stress of axial compression is 100～150MPa.Then, after 50 hours, 100 hours, 200 hours, 500 hours, 1000 hours and 2000 hours, measure the internal diameter of 6 points (axially 2 points spaced apart at equally spaced three positions spaced apart in the circumferential direction) of the aperture surface of the inner ring of each time period.In addition, in contrast, measure the internal diameter of above-mentioned 6 before axial compression enters.Thereafter, with test example 1-1 similarly, calculate the velocity of variation (size changing rate (%)) of the size of above-mentioned 6 of size after the each time inner ring aperture surface before keeping with respect to heating.In addition, about the inner ring of comparative example 1-1 and 1-3, with similarly above-mentioned, calculate size changing rate.By the coordinate graph of relation that represents aging time and size changing rate in Figure 16.In figure, solid line (filled circles) represents the inner ring of embodiment 1-1; Long and short dash line (hollow tetragon) represents the inner ring of comparative example 1-1; Two dot chain line (hollow triangle) represents the inner ring of comparative example 1-3.

Result is as shown in Figure 16 known, and compared with the inner ring of the inner ring of embodiment 1-1 and comparative example 1-1 and 3, ageing dimensional change is suppressed, and while use for a long time, size changing rate step-down, has sufficient dimensional stability.

(embodiment 1-4～1-7 and comparative example 1-8～1-12)

Utilize respectively two kinds of steel C and the D with the composition shown in table 7, be processed into regulation shape, manufacture respectively the moulding starting material of 9 kinds of outer rings for the manufacture of the spot contact bearing of model 6206 and inner ring.In addition, the steel D of table 7 is the JIS SUJ2 as bearing steel.

[table 7]

Then, to obtained moulding starting material, at Fig. 4, Figure 17～Figure 20, Fig. 6, under heat-treat condition shown in Figure 21～Figure 23, implement thermal treatment, then to the above-mentioned roller surface of the formation of the intermediate raw material after obtained thermal treatment, end face, shoulder face, inner peripheral surface (in the situation of inner ring), the part of periphery (in the situation of outer ring) is implemented attrition process, produce the chamfering with the cross section R shape of not grinding being connected with end face and inner peripheral surface (in the situation of inner ring), the chamfering of the cross section R shape of not grinding being connected with end face and periphery (in the situation of outer ring), the raceway member of the chamfering of the cross section rectilinear form not grinding being connected with end face and shoulder face is outer ring and the inner ring of embodiment 1-4～1-7 and comparative example 1-8～1-12.

Heat-treat condition shown in Figure 17 is, by moulding starting material be 1.2 at carbon potential, ammonia concentration is in the carbonitriding atmosphere of 5 volume %, after heating 7 hours at 860 ℃, oil cooling to 80 ℃, then, at-75 ℃, maintain one hour (deepfreeze), thereafter, at 180 ℃, heat 2 hours (temper) (experiment numbers 1-11).

Heat-treat condition shown in Figure 18 is, by moulding starting material be 1.2 at carbon potential, ammonia concentration is in the carbonitriding atmosphere of 2 volume %, after heating 5.5 hours at 860 ℃, oil cooling to 80 ℃,,, at 180 ℃, heat 2 hours (temper) (experiment numbers 1-12) thereafter.

Heat-treat condition shown in Figure 19 is, by moulding starting material be 1.2 at carbon potential, ammonia concentration is in the carbonitriding atmosphere of 2 volume %, after heating 9 hours at 860 ℃, oil cooling to 80 ℃,,, at 180 ℃, heat 2 hours (temper) (experiment numbers 1-13) thereafter.

Heat-treat condition shown in Figure 20 is, by moulding starting material be 1.2 at carbon potential, ammonia concentration is in the carbonitriding atmosphere of 5 volume %, after heating 4 hours at 850 ℃, oil cooling to 80 ℃,,, at 180 ℃, heat 2 hours (temper) (experiment numbers 1-14) thereafter.

Heat-treat condition shown in Figure 21 is that, in the carburizing atmosphere that is 1.2 at carbon potential by moulding starting material, after heating 5 hours at 850 ℃, oil cooling to 80 ℃ thereafter, heats 2 hours (temper) (experiment numbers 1-15) at 180 ℃.

Heat-treat condition shown in Figure 22 is, in the atmosphere that is 1.0 at carbon potential by moulding starting material, at 900 ℃, heat and within 0.5 hour, carried out after integral quenching, oil cooling to 80 ℃,,, at 180 ℃, heat 2 hours (temper) (experiment numbers 1-16) thereafter.

Heat-treat condition shown in Figure 23 is, in the carburizing atmosphere that is 1.2 at carbon potential by moulding starting material, after heating 7 hours at 930 ℃, then this heating, at 900 ℃, heat 0.5 hour, oil cooling to 80 ℃ subsequently thereafter, heats 2 hours (temper) (experiment numbers 1-17) at 180 ℃.

Table 8 represents kind, the heat-treat condition of the steel that the manufacture of the Internal and external cycle of embodiment 1-4～1-7 and comparative example 1-8～1-12 uses.

[table 8]

In addition, table 9 represents the thermal treatment quality on the groove portion surface (grind section) of the outer ring of embodiment 1-4～1-7; Table 10 represents the thermal treatment quality of the non-grind section of the outer ring of embodiment 1-4～1-7.In addition, table 11 represents the thermal treatment quality on the groove portion surface (grind section) of the outer ring of comparative example 1-8～1-12; Table 12 represents the thermal treatment quality of the non-grind section of the outer ring of comparative example 1-8～1-12.

As the thermal treatment quality on the groove portion surface (grind section) of table 9 and table 11, represent that respectively the Vickers' hardness apart from the dark position of surface (grind section) 50 μ m of groove portion is (in table, " Vickers' hardness "), the skin section remained austenite content of the position that the surperficial 10 μ m of distance are dark is (in table, " skin section remained austenite content "), the inside remained austenite content of the position that the surperficial 2mm of distance is dark is (in table, " inner remained austenite content "), carbon content the upper layer of the scope from surface to 10 μ m is (in table, " carbon content "), nitrogen content the upper layer of the scope from surface to 10 μ m is (in table, " nitrogen content "), precipitate form, vanadium the upper layer of the scope from surface to 10 μ m is that the area occupation ratio of precipitate (particle of the particle of particle diameter 0.2～2 μ m being made up of vanadium carbonitride and particle diameter 0.2～2 μ m being made up of vanadium nitride) is (in table, " vanadium is the area occupation ratio of precipitate ") and the upper layer of scope from surface to 10 μ m the area occupation ratio of precipitate of nitrogenate (in table, " area occupation ratio of the precipitate of nitrogenate ").

In addition, as the thermal treatment quality of the non-grind section of table 10 and table 12, represent that respectively the Vickers' hardness apart from the dark position of surperficial 50 μ m of non-grind section is (in table, " Vickers' hardness "), carbon content the upper layer of the scope from surface to 10 μ m is (in table, " carbon content "), nitrogen content the upper layer of the scope from surface to 10 μ m is (in table, " nitrogen content ") and the upper layer of scope from surface to 10 μ m particle diameter 10 μ m more than the having or not (in table of thick carbon compound particle, " thick carbon compound particles more than particle diameter 10 μ m ").

[table 10]

[table 12]

The accompanying drawing of the result in addition, the groove portion surface (grind section) that represents the outer ring that utilizes electron microscope observation embodiment 1-4 being obtained substitutes photo and is shown in Figure 24.In addition, will represent that utilizing the groove portion surface (grind section (in figure, A)) of outer ring of electron microscope observation embodiment 1-4 and the accompanying drawing of the result that non-grind section (in figure, B) surface obtains to substitute photo is shown in Figure 25.In addition, in contrast, will represent that utilizing the groove portion surface (grind section (in figure, C)) of outer ring of electron microscope observation comparative example 1-12 and the accompanying drawing of the result that non-grind section (in figure, D) surface obtains to substitute photo is shown in Figure 26.

From the result shown in table 9 and table 10, implement by the moulding starting material to being obtained by steel C the outer ring that the embodiment 1-4 obtaining is processed in carbonitriding, in grind section, the Vickers' hardness apart from the dark position of surface (grind section) 50 μ m of groove portion is 810; Skin section remained austenite content apart from the dark position of above-mentioned surperficial 10 μ m is 43 volume %; Carbon content the upper layer of the scope from above-mentioned surface to 10 μ m is 1.4 quality %; Nitrogen content the upper layer of the scope from above-mentioned surface to 10 μ m is 0.4 quality %; The area occupation ratio of the precipitate of the nitrogenate the upper layer of the scope from surface to 10 μ m is 13%; Inside remained austenite content apart from the dark position of above-mentioned surperficial 2mm is 15 volume %; Vanadium the upper layer of the scope from above-mentioned surface to 10 μ m is that the area occupation ratio of precipitate is 5%.

In addition we know,, in non-grind section, the Vickers apart from the dark position of surperficial 50 μ m of non-grind section is 735; Carbon content the upper layer of the scope from surface to 10 μ m is 0.8 quality %; Nitrogen content the upper layer of the scope from surface to 10 μ m is 1.0 quality %.

In addition, from the result shown in Figure 24, on the groove portion surface (grind section) of the outer ring of embodiment 1-1, there is the nitride particles below particle diameter 500nm.In addition, in the non-grind section of the outer ring of embodiment 1-1, as shown in figure 25, not thick carbon compound particle (figure, with reference to B) more than the particle diameter 10 μ m of the upper layer of the scope from surface to 10 μ m.

In addition, from the result shown in table 9 and table 10, implemented to implement again after carbonitriding is processed the outer ring of the embodiment 1-5 that deepfreeze obtains by moulding starting material to being obtained by steel C, in grind section, the Vickers' hardness apart from the dark position of surface (grind section) 50 μ m of groove portion is 880; Skin section remained austenite content apart from the dark position of above-mentioned surperficial 10 μ m is 22 volume %; Inside remained austenite content apart from the dark position of above-mentioned surperficial 2mm is 5 volume %; Carbon content the upper layer of the scope from above-mentioned surface to 10 μ m is 1.4 quality %; Nitrogen content the upper layer of the scope from above-mentioned surface to 10 μ m is 0.6 quality %; Vanadium the upper layer of the scope from above-mentioned surface to 10 μ m is that the area occupation ratio of precipitate is 6%; The area occupation ratio of the precipitate of the nitrogenate the upper layer of the scope from above-mentioned surface to 10 μ m is 12%.

In addition we know,, in non-grind section, the Vickers' hardness apart from the dark position of surperficial 50 μ m of non-grind section is 800; Carbon content the upper layer of the scope from above-mentioned surface to 10 μ m is 0.8 quality %; Nitrogen content the upper layer of the scope from above-mentioned surface to 10 μ m is 1.3 quality %; Not thick carbon compound particle more than the particle diameter 10 μ m the upper layer of the scope from above-mentioned surface to 10 μ m.

Known, in embodiment 1-4, except the ammonia concentration of carbonitriding atmosphere being made as to 2 volume % and heating and carrying out 5.5 hours the outer ring of the embodiment 1-6 that same operation obtains, in grind section, the Vickers' hardness apart from the dark position of surperficial (grind section) 50 μ m of groove portion is 780; Skin section remained austenite content apart from the dark position of above-mentioned surperficial 10 μ m is 45 volume %; Inside remained austenite content apart from the dark position of above-mentioned surperficial 2mm is 10 volume %; Carbon content the upper layer of the scope from above-mentioned surface to 10 μ m is 1.2 quality %; Nitrogen content the upper layer of the scope from above-mentioned surface to 10 μ m is 0.2 quality %; Vanadium the upper layer of the scope from above-mentioned surface to 10 μ m is that the area occupation ratio of precipitate is 3%; The area occupation ratio of the precipitate of the nitrogenate the upper layer of the scope from above-mentioned surface to 10 μ m is 8%.

In addition we know,, in non-grind section, the Vickers' hardness apart from the dark position of surperficial 50 μ m of non-grind section is 720; Carbon content the upper layer of the scope from above-mentioned surface to 10 μ m is 0.8 quality %; Nitrogen content the upper layer of the scope from above-mentioned surface to 10 μ m is 1.1 quality %; Not thick carbon compound particle more than the particle diameter 10 μ m the upper layer of the scope from above-mentioned surface to 10 μ m.

Known equally, in embodiment 1-4 except the ammonia concentration of carbonitriding atmosphere being made as to 2 volume % and heating were carried out same operation 9 hours and the outer ring of the embodiment 1-7 that obtains, in grind section, the Vickers' hardness apart from the dark position of surface (grind section) 50 μ m of groove portion is 755; Skin section remained austenite content apart from the dark position of above-mentioned surperficial 10 μ m is 49 volume %; Inside remained austenite content apart from the dark position of above-mentioned surperficial 2mm is 14 volume %; Carbon content the upper layer of the scope from above-mentioned surface to 10 μ m is 1.6 quality %; Nitrogen content the upper layer of the scope from above-mentioned surface to 10 μ m is 0.3 quality %; Vanadium the upper layer of the scope from above-mentioned surface to 10 μ m is that the area occupation ratio of precipitate is 4%; The precipitate area occupation ratio of the nitrogenate the upper layer of the scope from above-mentioned surface to 10 μ m is 17%.

In addition we know,, in non-grind section, the Vickers' hardness apart from the dark position of surperficial 50 μ m of non-grind section is 730; Carbon content the upper layer of the scope from above-mentioned surface to 10 μ m is 0.8 quality %; Nitrogen content the upper layer of the scope from above-mentioned surface to 10 μ m is 1.4 quality %, not thick carbon compound particles more than the particle diameter 10 μ m the upper layer of the scope from above-mentioned surface to 10 μ m.

On the groove portion surface (grind section) of the outer ring of the each example of embodiment 1-5～1-7, all with the outer ring of the embodiment 1-4 shown in Figure 24 similarly, have the nitride particles below particle diameter 500nm.

Groove portion surface (grind section) after the fine grinding processing of the outer ring of the each example of embodiment 1-5～1-7, upper layer on the surface from having carried out above-mentioned fine grinding processing to the scope of 10 μ m, there is the particle being formed by nitride below particle diameter 500nm, the area occupation ratio of the precipitate of the nitrogenate the upper layer of the scope from above-mentioned surface to 10 μ m is 5～20%, therefore the hardness on surface has improved, even while use, also can relax the impression that generates while nipping impurity stress concentration around in the lubricating oil that is mixed with impurity.

Enlightened by these results, as the outer ring of embodiment 1-5～1-7, by forming carbonitrided case in non-grind section, in non-grind section, being suppressed of over cargurization tissue.

On the other hand, from the result shown in table 11 and table 12, the outer ring of the comparative example 1-12 obtaining by the moulding starting material enforcement carburizing treatment to being obtained by steel C is on the surface of non-grind section nonnitrogenous (N).In addition, from the result shown in Figure 26, in the non-grind section (in figure, with reference to C) of the outer ring of comparative example 1-12, have thick carbon compound particles more than particle diameter 10 μ m, therefore produced over cargurization tissue.

(test example 1-4)

Then, the outer ring to embodiment 1-4～1-7 and comparative example 1-8～1-12 and inner ring have carried out longevity test and compressive strength test in impurity oil respectively.In the time carrying out in impurity oil longevity test, using identical with embodiment 1-4～1-7 and the each example of comparative example 1-8～1-12 a pair of outer ring of manufacturing as embodiment and comparative example and inner ring and by the ball combination high-carbon-chromium bearing steel (JIS SUJ2) being implemented after carbonitriding is processed to quench again, temper is made, the spot contact bearing of assembling model 6206, offers longevity test in impurity oil by obtained spot contact bearing.In impurity oil, the test conditions of longevity test is same with above-mentioned table 2.In addition, table 13 represents the test conditions of compressive strength test.Compressive strength test is following test,, with A Musila (Amsler) trier, become the position of 180 ° to clamp along footpath direction at the second position with the first position of above-mentioned Zhou Fangxiang with being moved into along Zhou Fangxiang at the first position of the Zhou Fangxiang of 6206 outer rings, the first position and the second position are with the speed of 0.5mm/min, along connecting the first position direction vertical with the axis with 6206 outer rings at the second position, move in the mode approaching, make thus above-mentioned 6206 race deformations, it is destroyed, then evaluate the radial loading while destruction.The ratio of the load of load when compressive strength rate is 6206 outer ring destroyed of each embodiment, comparative example during with respect to the 6206 outer ring destroyed of comparative example 1-9.Then, these be the results are shown in to table 14.

[table 13]

	Compressive strength test
		Test specimen bearing designation	6206 outer rings
Loaded speed	0.5mm/min
		N number	5

[table 14]

Result is as shown in Table 14 known, possess the outer ring of embodiment 1-4～1-7 and the spot contact bearing of inner ring of the steel C of the composition of use table 7, compared with possessing the outer ring of comparative example 1-8～1-10 and the spot contact bearing of inner ring that uses steel D, extended the life-span in impurity oil, and the ultimate compression strength of its outer ring is also high.

On the other hand, result is as shown in Table 14 known, possess the moulding starting material that the identical steel C of the steel by used with the outer ring of embodiment 1-4～1-7 is obtained and implemented the spot contact bearing of the outer ring of the comparative example 1-12 of carburizing treatment, compared with possessing the spot contact bearing of outer ring of the comparative example 1-8～1-10 that uses steel D, the ultimate compression strength of its outer ring is low.On the other hand, known, possess by the moulding starting material enforcement carbonitriding to being obtained by steel C and process the outer ring of embodiment 1-4～1-7 and the spot contact bearing of inner ring that obtain, in impurity oil, the ultimate compression strength both sides of life-span and outer ring thereof are improved.

Like this, in comparative example 1-10,1-12, find, in the non-grind section that is present in the part except above-mentioned groove portion, have thick carbon compound particles more than particle diameter 10 μ m, produced the over cargurization tissues such as free carbide, this over cargurization tissue becomes the starting point of stress concentration, makes thus the ultimate compression strength of rolling bearing reduce.And, in embodiment 1-4～1-7, by the steel of regulation are implemented to carbonitriding processing under defined terms, although the groove portion at rolling bearing forms the few long lifetime tissue (carburized structure) of precipitate, but can not produce thick carbon compound particles more than particle diameter 10 μ m in non-grind section, the generation of the over cargurization tissues such as free carbide is suppressed, and the reduction of ultimate compression strength is suppressed, and can realize higher rolling fatigue life.

Therefore, enlightened by these results, as embodiment 1-4～1-7, implement carbonitriding according to the moulding starting material by being obtained by the steel C forming of table 7 and process the raceway member obtaining, can not form over cargurization tissue in non-grind section, can obtain life-span and all rolling bearings of excellence of ultimate compression strength in impurity oil.

(embodiment 2-1,2-2 and comparative example 2-1～2-7, reference example 2-1～2-3)

Respectively two kinds of steel A and the B with the composition shown in table 1 are processed into regulation shape, produce in the part that forms roller surface and there is spot contact bearing (model 6206) Internal and external cycle of grind and there are spot contact bearing (model 6206) the rolling body moulding starting material separately of grind in the part of formation rolling surface.The steel B of table 1 is the JIS SUJ2 as bearing steel.In addition, the diameter of rolling body is 9.525mm.

Then, to obtained moulding starting material, under the heat-treat condition shown in Fig. 3～Figure 12, Figure 27～Figure 29, implement thermal treatment, then the part of the above-mentioned rolling surface of formation of the intermediate raw material of the rolling body after the part of the above-mentioned roller surface of formation of the each intermediate raw material to the Internal and external cycle after obtained thermal treatment and the thermal treatment that obtains is implemented attrition process respectively, produces the spot contact bearing of embodiment 2-1 and 2-2 and the spot contact bearing of comparative example 2-1～2-7, reference example 2-1～2-3.

Heat-treat condition shown in Fig. 3 is, by moulding starting material be 1.1 at carbon potential, ammonia concentration is in the carbonitriding atmosphere of 2 volume %, after heating 7 hours at 860 ℃, oil cooling to 80 ℃,,, at 180 ℃, heat 2 hours (temper) (experiment numbers 2-1) thereafter.

Heat-treat condition shown in Fig. 8 is, by moulding starting material be 1.2 at carbon potential, ammonia concentration is in the carbonitriding atmosphere of 2 volume %, after heating 4 hours at 850 ℃, oil cooling to 80 ℃,,, at 160 ℃, heat 2 hours (temper) (experiment numbers 2-2) thereafter.

Heat-treat condition shown in Figure 27 is, by moulding starting material be 1.1 at carbon potential, ammonia concentration is in the carbonitriding atmosphere of 2 volume %, after heating 7 hours at 860 ℃, oil cooling to 80 ℃, then, at-55 ℃ cooling one hour (deepfreeze), thereafter, at 200 ℃, heat 2 hours (temper) (experiment numbers 2-3).

Heat-treat condition shown in Figure 28 is, by moulding starting material be 1.1 at carbon potential, ammonia concentration is in the carbonitriding atmosphere of 2 volume %, after heating 5 hours at 850 ℃, oil cooling to 80 ℃,,, at 180 ℃, heat 2 hours (temper) (experiment numbers 2-4) thereafter.

Heat-treat condition shown in Figure 29 is, by moulding starting material be 1.1 at carbon potential, ammonia concentration is in the carbonitriding atmosphere of 2 volume %, after heating 5 hours at 860 ℃, oil cooling to 80 ℃, then, at-75 ℃ cooling one hour (deepfreeze), thereafter, at 200 ℃, heat 2 hours (temper) (experiment numbers 2-5).

Heat-treat condition shown in Fig. 6 is, in the atmosphere that is 0.8 at carbon potential by moulding starting material, at 830 ℃, heat and within 0.5 hour, carried out after integral quenching, oil cooling to 80 ℃,,, at 180 ℃, heat 2 hours (temper) (experiment numbers 2-6) thereafter.

Heat-treat condition shown in Fig. 7 is that, in the carburizing atmosphere that is 1.2 at carbon potential by moulding starting material, after heating 5 hours at 850 ℃, oil cooling to 80 ℃ thereafter, heats 2 hours (temper) (experiment numbers 2-7) at 160 ℃.

Heat-treat condition shown in Fig. 9 is, in the atmosphere that is 0.8 at carbon potential by moulding starting material, at 900 ℃, heat and within 0.5 hour, carried out after integral quenching, oil cooling to 80 ℃,,, at 180 ℃, heat 2 hours (temper) (experiment numbers 2-8) thereafter.

Heat-treat condition shown in Figure 10 is that, in the carburizing atmosphere that is 1.2 at carbon potential by moulding starting material, after heating 7 hours at 900 ℃, oil cooling to 80 ℃ thereafter, heats 2 hours (temper) (experiment numbers 2-9) at 160 ℃.

Heat-treat condition shown in Figure 11 is, by moulding starting material be 1.2 at carbon potential, ammonia concentration is in the carbonitriding atmosphere of 1 volume %, after heating 7 hours at 860 ℃, oil cooling to 80 ℃,,, at 180 ℃, heat 2 hours (temper) (experiment numbers 2-10) thereafter.

Heat-treat condition shown in Figure 12 is, by moulding starting material be 1.2 at carbon potential, ammonia concentration is in the carbonitriding atmosphere of 15 volume %, after heating 7 hours at 860 ℃, oil cooling to 80 ℃,,, at 180 ℃, heat 2 hours (temper) (experiment numbers 2-11) thereafter.

Heat-treat condition shown in Fig. 4 is, by moulding starting material be 1.2 at carbon potential, ammonia concentration is in the carbonitriding atmosphere of 5 volume %, after heating 7 hours at 860 ℃, oil cooling to 80 ℃,,, at 180 ℃, heat 2 hours (temper) (experiment numbers 2-12) thereafter.

Heat-treat condition shown in Fig. 5 is, by moulding starting material be 1.0 at carbon potential, ammonia concentration is in the carbonitriding atmosphere of 2 volume %, after heating 7 hours at 860 ℃, oil cooling to 80 ℃,,, at 180 ℃, heat 2 hours (temper) (experiment numbers 2-13) thereafter.

In addition, in embodiment 2-1, inner ring is to manufacture under the heat-treat condition shown in Fig. 3 (experiment numbers 2-1); Rolling body is to manufacture under the heat-treat condition shown in Fig. 8 (experiment numbers 2-2); Outer ring is to manufacture under the heat-treat condition shown in Figure 27 (experiment numbers 2-3).

In addition, in embodiment 2-2, inner ring is to manufacture under the heat-treat condition shown in Figure 28 (experiment numbers 2-4); Rolling body is to manufacture under the heat-treat condition shown in Fig. 8 (experiment numbers 2-2); Outer ring is to manufacture under the heat-treat condition shown in Figure 29 (experiment numbers 2-5).

Outer ring, inner ring and the rolling body of the spot contact bearing of comparative example 2-1 is respectively to manufacture under the heat-treat condition shown in Fig. 6 (experiment numbers 2-6).

The outer ring of the spot contact bearing of comparative example 2-2, comparative example 2-4～comparative example 2-7 and inner ring are respectively to manufacture under the heat-treat condition (experiment numbers 2-8,2-9,2-10,2-11) shown in the heat-treat condition shown in Fig. 7 (experiment numbers 2-7), Fig. 9～Figure 12.The outer ring of the spot contact bearing of comparative example 2-3 and inner ring are to manufacture under the heat-treat condition shown in Fig. 8 (experiment numbers 2-2).The outer ring of the spot contact bearing of reference example 2-1 and inner ring are to manufacture under the heat-treat condition shown in Fig. 3 (experiment numbers 2-1).In addition, the outer ring of the spot contact bearing of reference example 2-2 and 2-3 and inner ring are respectively to manufacture under the heat-treat condition (experiment numbers 2-13) shown in the heat-treat condition shown in Fig. 4 (experiment numbers 2-12) and Fig. 5.The rolling body of the spot contact bearing of comparative example 2-2～comparative example 2-7, reference example 2-1～2-3 is respectively to manufacture under the heat-treat condition shown in Fig. 8 (experiment numbers 2-2).

(test example 2-1)

About the outer ring of embodiment 2-1 and 2-2, the spot contact bearing inner ring used of embodiment 2-1 and 2-2, comparative example 2-1～2-7, the outer ring of reference example 2-1～2-3, to the Vickers' hardness (Rockwell C hardness) of the dark position of the surface apart from groove portion (grind section) 50 μ m, apart from the skin section remained austenite content of the dark position of above-mentioned surperficial 10 μ m, carbon content the upper layer of the scope from above-mentioned surface to 10 μ m, nitrogen content the upper layer of the scope from above-mentioned surface to 10 μ m, precipitate form, and vanadium is that the area occupation ratio of precipitate (particle of the particle of particle diameter 0.2～2 μ m being made up of vanadium carbonitride and particle diameter 0.2～2 μ m being made up of vanadium nitride) is studied.To the Vickers' hardness (Rockwell C hardness) apart from the dark position of surperficial 50 μ m of the spot contact bearing of embodiment 2-1 and 2-2 rolling body used, apart from the skin section remained austenite content of the dark position of above-mentioned surperficial 10 μ m, carbon content the upper layer of the scope from above-mentioned surface to 10 μ m, nitrogen content the upper layer of the scope from surface to 10 μ m, precipitate form, and vanadium is that the area occupation ratio of precipitate (particle of the particle of particle diameter 0.2～2 μ m being made up of vanadium carbonitride and particle diameter 0.2～2 μ m being made up of vanadium nitride) is studied.

In order to measure the hardness of upper layer of essence, apart from the Vickers' hardness of the dark position of surperficial 50 μ m, after respectively above-mentioned Internal and external cycle and rolling body being cut off along depth direction from surface, measure being pressed into Vickers pressure head apart from the above-mentioned surperficial 50 dark positions of μ m.In addition, Rockwell C hardness is by converting to try to achieve to measured Vickers' hardness.Apart from the skin section remained austenite content of the dark position of above-mentioned surperficial 10 μ m, carry out electrolytic polishing by the degree of depth from surface to 10 μ m of the groove portion to above-mentioned inner ring, and the surperficial remained austenite content of measuring after electrolytic polishing is tried to achieve.From surface to the carbon content of the scope of 10 μ m and from surface to the nitrogen content of the scope of 10 μ m, by after above-mentioned Internal and external cycle and rolling body are cut off along depth direction respectively from surface, measure each content of the scope from above-mentioned surface to 10 μ m and try to achieve respectively.

Above-mentioned precipitate form, after above-mentioned Internal and external cycle and rolling body are cut off along depth direction respectively from surface, observes and evaluates to the scope of 10 μ m from above-mentioned surface.Vanadium is the area occupation ratio of precipitate (particle of the particle of particle diameter 0.2～2 μ m being made up of vanadium carbonitride and particle diameter 0.2～2 μ m being made up of vanadium nitride), after above-mentioned Internal and external cycle and rolling body are cut off along depth direction respectively from surface, in the scope from above-mentioned surface to 10 μ m, measure.In addition, above-mentioned precipitate form and vanadium are the area occupation ratio of precipitate (particle of the particle of particle diameter 0.2～2 μ m being made up of vanadium carbonitride and particle diameter 0.2～2 μ m being made up of vanadium nitride), at 800 μ m ²mensuration visual field in, acceleration voltage: 15.0kV, irradiate electric current: 2.016 × 10 ^-7a and scanning multiplying power: under the condition of 3000 times, utilize field emission type electron probe microanalyzer, carbon, nitrogen and vanadium are made to reflection, calculate area occupation ratio by image processing apparatus.

In addition, about each spot contact bearing of embodiment 2-1 and 2-2 and comparative example 2-1～2-7, reference example 2-1～2-3, to the life-span index an index of the life-span in the lubricating oil that is mixed with impurity (life-span in impurity oil) and static load ability be that raceway circle depth of indentation is studied.

In impurity oil, the life-span tests under the conditions shown in Table 2.About the life-span in above-mentioned impurity oil, use judgment standard below to evaluate.

(judgment standard)

Zero: the more than 8 times of the L10 life-span of the spot contact bearing of comparative example 2-1.

×: 8 times of the L10 life-span of the spot contact bearing of not enough comparative example 2-1.

In addition, raceway circle depth of indentation, by the ball of the spot contact bearing of embodiment 2-1 and 2-2 and comparative example 2-1～2-7, reference example 2-1～2-3 is configured on plummet, and apply the load of 14.7kN from vertical top, be then determined at three-dimensional measuring instrument the depth of indentation that produces the part of maximum stress in the raceway circle of above-mentioned spot contact bearing and evaluate.Raceway circle depth of indentation is the value of the summation of the depth of indentation that produces on the depth of indentation that produces on inner ring and outer ring.About above-mentioned raceway circle depth of indentation, use judgment standard below to evaluate.

(judgment standard)

Zero: depth of indentation is below 0.635 μ m

×: depth of indentation is greater than 0.635 μ m

In addition, above-mentioned " 0.635 μ m " is the limit set deformation volume that does not hinder smooth and easy rotation of the spot contact bearing of rolling body diameter while being 9.525mm.This value is, suppose in the tolerable limit of the distortion causing at the impression of the rolling bearing entirety with rolling body diameter (9.525mm) × 1/10000 judgement, distortion that impression causes respectively equably (respectively account for entirety 1/3) results from inner ring, outer ring and rolling body, the value that depth of indentation of inner ring and the depth of indentation of outer ring are added together be the distortion that causes of the impression of rolling bearing entirety tolerable limit 2/3,2/3 value of obtaining as permissible value of the tolerable limit of the distortion therefore impression of rolling bearing entirety being caused.

Table 15 represents the outer ring to embodiment 2-1 and 2-2, and the kind of the steel that use of the spot contact bearing of embodiment 2-1 and 2-2 inner ring used and rolling body, heat-treat condition, apart from the Vickers' hardness (Rockwell C hardness) of the dark position of surperficial 50 μ m, apart from the remained austenite content of the dark position of surperficial 10 μ m, carbon content the upper layer of the scope from surface to 10 μ m, nitrogen content the upper layer of the scope from surface to 10 μ m, precipitate form, vanadium is the area occupation ratio of precipitate, and the result that in the impurity oil of the spot contact bearing of embodiment 2-1 and 2-2, life-span and raceway circle depth of indentation are studied.

In addition, table 16 represents comparative example 2-1～2-7, the kind of the steel that the outer inner ring of reference example 2-1～2-3 uses, heat-treat condition, apart from the Vickers' hardness (Rockwell C hardness) of the dark position of surperficial 50 μ m, apart from the remained austenite content of the dark position of surperficial 10 μ m, carbon content the upper layer of the scope from surface to 10 μ m, nitrogen content the upper layer of the scope from surface to 10 μ m, precipitate form, vanadium is the area occupation ratio of precipitate, and comparative example 2-1～2-7, the result that in the impurity oil of the spot contact bearing of reference example 2-1～2-3, life-span and raceway circle depth of indentation are studied.

In addition, in table 15 and 16, " Vickers' hardness (Rockwell C hardness) " represents the Vickers' hardness (Rockwell C hardness) of the position dark apart from surperficial 50 μ m; " remained austenite content (volume %) " represents the remained austenite content of the position dark apart from surperficial 10 μ m; " carbon content (quality %) " and " nitrogen content (quality %) " represents respectively carbon content and the nitrogen content the upper layer of the scope from surface to 10 μ m; " vanadium is the area occupation ratio (%) of precipitate " represents the particle of the particle diameter being made up of vanadium nitride 0.2～2 μ m the upper layer of the scope from surface to 10 μ m and the area occupation ratio of the particle that the particle of particle diameter 0.2～2 μ m that is made up of vanadium carbonitride is added together.

Result is as shown in Table 15 known, and in the impurity oil of the spot contact bearing of embodiment 2-1 and 2-2, the life-span is the more than 12 times of L10 life-span of the spot contact bearing of comparative example 2-1.In addition, the raceway circle depth of indentation of the spot contact bearing of embodiment 2-1 and 2-2 is respectively 0.35 μ m and 0.38 μ m, for the limit that does not hinder smooth and easy rotation of spot contact bearing be set deformation volume (0.635 μ m) below.

Therefore known, according to the combination of the outer ring of embodiment 2-1 and 2-2 and inner ring, the long lifetime of rolling bearing can be realized, and sufficient static load ability can be guaranteed.

On the other hand, result is as shown in Table 16 known, in the impurity oil of comparative example 2-2～2-4 and 7 spot contact bearing 8 times (1～3 times) in the L10 life-span of the spot contact bearing of not enough comparative example 2-1 of life-span, compared with the spot contact bearing of embodiment 2-1 and 2-2, lifetime in impurity oil.In addition we know, the raceway circle depth of indentation of comparative example 2-1～2-4 and 7 spot contact bearing is greater than 0.635 μ m, for (0.82～2.0 μ m), for the limit that does not hinder smooth and easy rotation of spot contact bearing is more than set deformation volume.

In addition, result is as shown in Table 16 known, in the impurity oil of the spot contact bearing of comparative example 2-5,2-6, the life-span is 8 times above (being respectively 10 times (comparative example 2-5) and 12 times (comparative example 2-6)) in the L10 life-span of the spot contact bearing of comparative example 2-1, but raceway circle depth of indentation is greater than 0.635 μ m (being respectively 1.4 μ m (comparative example 2-5) and 1.6 μ m (comparative example 2-6)), for the limit that does not hinder smooth and easy rotation of spot contact bearing is more than set deformation volume.

In addition, result is as shown in Table 16 known, in the spot contact bearing of reference example 2-1～2-3, in impurity oil, life-span and raceway circle depth of indentation are all spendable levels, but compared with the spot contact bearing of embodiment 2-1 and 2-2, raceway circle depth of indentation is elongated, and compared with the spot contact bearing of embodiment 2-1 and 2, static load ability is low.

Therefore, from these results, in the spot contact bearing as rolling bearing, have by use following prescribed value character driving circle (inner ring) and there is the fixed ring (outer ring) of the character of following prescribed value, long lifetime can be realized, static load ability can be improved in addition.The driving circle (inner ring) of the described character with following prescribed value is implemented carbonitriding processing for the moulding starting material by above-mentioned steel A is processed and is obtained, described carbonitriding is treated in the carbonitriding atmosphere of carbon potential 0.9～1.3 and ammonia concentration 2～5 volume %, heats the then processing of chilling at 850～900 ℃; The fixed ring (outer ring) of the described character with following prescribed value is for by after implementing above-mentioned carburizing treatment to above-mentioned moulding starting material, then deepfreeze at obtained intermediate raw material is implemented to-50～-100 ℃ and obtaining.

(1) inner ring:

Carbon content the upper layer of the scope from surface to 10 μ m is 1.1～1.6 quality %; Vickers' hardness apart from the dark position of surperficial 50 μ m is 740～900 (Rockwell C hardness is 62～67); Remained austenite content apart from the dark position of surperficial 10 μ m is 20～55 volume %; Nitrogen content the upper layer of the scope from surface to 10 μ m is 0.1～1.0 quality %; At the upper layer from surface to the scope of 10 μ m, the particle of particle diameter 0.2～2 μ m that there is the particle of particle diameter 0.2～2 μ m being formed by vanadium nitride and/or formed by vanadium carbonitride, and the area occupation ratio of the particle of the particle of particle diameter 0.2～2 μ m being made up of above-mentioned vanadium nitride the upper layer of the scope from above-mentioned surface to 10 μ m and/or particle diameter 0.2～2 μ m being made up of vanadium carbonitride is 1～10%.

(2) outer ring:

The content of the carbon the upper layer of the scope from surface to 10 μ m is 1.1～1.6 quality %; Vickers' hardness apart from the dark position of surperficial 50 μ m is 800～940 (Rockwell C hardness is 64～68); Remained austenite content apart from the dark position of surperficial 10 μ m is 5～30 volume %; The content of the nitrogen the upper layer of the scope from surface to 10 μ m is 0.1～1.0 quality %; At the upper layer from surface to the scope of 10 μ m, the particle of particle diameter 0.2～2 μ m that there is the particle of particle diameter 0.2～2 μ m being formed by vanadium nitride and/or formed by vanadium carbonitride, and the area occupation ratio of the particle of the particle of particle diameter 0.2～2 μ m being made up of above-mentioned vanadium nitride the upper layer of the scope from surface to 10 μ m and/or particle diameter 0.2～2 μ m being made up of vanadium carbonitride is 1～10%.

(embodiment 2-3 and comparative example 2-8～2-12)

Steel C shown in table 7 and D are processed into respectively to regulation shape, produce the moulding starting material in the part that forms roller surface with the outer inner ring of spot contact bearing (model 6206) of grind.In addition, the steel D of table 5 is that bearing steel is JIS SUJ2.

Then, to obtained moulding starting material, under the heat-treat condition shown in Figure 17 and Fig. 6, Figure 20～Figure 23, implement thermal treatment, in addition, implement the precision work based on grinding, make the outer ring as embodiment 2-3 and the comparative example 2-8～2-12 of raceway member.

Heat-treat condition shown in Figure 17 is, by moulding starting material be 1.2 at carbon potential, ammonia concentration is in the carbonitriding atmosphere of 5 volume %, after heating 7 hours at 860 ℃, oil cooling to 80 ℃, then, at-75 ℃, maintain one hour (deepfreeze), thereafter, at 180 ℃, heat 2 hours (temper).

Heat-treat condition shown in Figure 21 is that, in the carburizing atmosphere that is 1.2 at carbon potential by moulding starting material, after heating 5 hours at 850 ℃, oil cooling to 80 ℃ thereafter, heats 2 hours (temper) at 180 ℃.

Heat-treat condition shown in Figure 20 is, by moulding starting material be 1.2 at carbon potential, ammonia concentration is in the carbonitriding atmosphere of 5 volume %, after heating 4 hours at 850 ℃, oil cooling to 80 ℃ thereafter, heats 2 hours (temper) at 180 ℃.

Heat-treat condition shown in Figure 22 is, in the atmosphere that is 1.0, heats and within 0.5 hour, carried out after integral quenching at 900 ℃ moulding starting material at carbon potential, and oil cooling to 80 ℃ thereafter, heats 2 hours (temper) at 180 ℃.

Heat-treat condition shown in Figure 23 is, in the carburizing atmosphere that is 1.2 at carbon potential by moulding starting material, after heating 7 hours at 930 ℃, then oil cooling to 80 ℃ is subsequently heated in this heating 0.5 hour at 900 ℃,,, at 180 ℃, heat 2 hours (temper) thereafter.

(test example 2-2)

About the outer ring of embodiment 2-3 and comparative example 2-8～2-12, thermal treatment quality is studied.

Table 17 represents that the outer ring of embodiment 2-3 and comparative example 2-8～2-12 manufactures kind, the heat-treat condition of steel used.

[table 17]

In addition, table 18 represents the thermal treatment quality of groove portion surface (grind section); Table 19 represents the thermal treatment quality of non-grind section.As the thermal treatment quality of groove portion surface (grind section), represent that respectively the Vickers' hardness of the position that surface (grind section) 50 μ m apart from groove portion are dark is (in table, " Vickers' hardness "), the skin section remained austenite content of the position that the surperficial 10 μ m of distance are dark is (in table, " skin section remained austenite content "), the inside remained austenite content of the position that the above-mentioned surperficial 2mm of distance is dark is (in table, " inner remained austenite content "), carbon content the upper layer of the scope from above-mentioned surface to 10 μ m is (in table, " carbon content "), nitrogen content the upper layer of the scope from above-mentioned surface to 10 μ m is (in table, " nitrogen content "), precipitate form, vanadium the upper layer of the scope from above-mentioned surface to 10 μ m is that the area occupation ratio of precipitate (particle of the particle of particle diameter 0.2～2 μ m being made up of vanadium carbonitride and particle diameter 0.2～2 μ m being made up of vanadium nitride) is (in table, " vanadium is the area occupation ratio of precipitate ") and the upper layer of scope from above-mentioned surface to 10 μ m the area occupation ratio of precipitate of nitrogenate (in table, " area occupation ratio of the precipitate of nitrogenate ").

In addition, as the thermal treatment quality of non-grind section, represent that respectively the Vickers' hardness apart from the dark position of surperficial 50 μ m of non-grind section is (in table, " Vickers' hardness "), carbon content the upper layer of the scope from above-mentioned surface to 10 μ m is (in table, " carbon content "), nitrogen content the upper layer of the scope from above-mentioned surface to 10 μ m is (in table, " nitrogen content ") and the upper layer of scope from above-mentioned surface to 10 μ m particle diameter 10 μ m more than the having or not (in table of thick carbon compound particle, " thick carbon compound particles more than particle diameter 10 μ m ").

[table 19]

From the result shown in table 18 and table 19, implemented to implement again after carbonitriding is processed the outer ring of the embodiment 2-3 that deepfreeze obtains by moulding starting material to being obtained by steel C, in grind section, be 880 apart from the Vickers' hardness of the dark position of surface (grind section) the 50 μ m of groove portion; Skin section remained austenite content apart from the dark position of above-mentioned surperficial 10 μ m is 22 volume %; Inside remained austenite content apart from the dark position of above-mentioned surperficial 2mm is 5 volume %; Carbon content the upper layer of the scope from above-mentioned surface to 10 μ m is 1.4 quality %; Nitrogen content the upper layer of the scope from above-mentioned surface to 10 μ m is 0.6 quality %; Vanadium the upper layer of the scope from above-mentioned surface to 10 μ m is that the area occupation ratio of precipitate is 6%; The area occupation ratio of the precipitate of the nitrogenate the upper layer of the scope from above-mentioned surface to 10 μ m is 12%.

In addition, in non-grind section, be 800 apart from the Vickers' hardness of the dark position of the surface 50 μ m of non-grind section; Carbon content the upper layer of the scope from above-mentioned surface to 10 μ m is 0.8 quality %; Nitrogen content the upper layer of the scope from above-mentioned surface to 10 μ m is 1.3 quality %, not thick carbon compound particles more than the particle diameter 10 μ m the upper layer of the scope from above-mentioned surface to 10 μ m.

In addition, on the groove portion surface (grind section) of the outer ring of embodiment 2-3, have the nitride particles below particle diameter 500nm.

The groove portion surface (grind section) of the outer ring after the fine grinding processing of embodiment 2-3, from the surface of having carried out the processing of above-mentioned fine grinding to the upper layer of the scope of 10 μ m, there is the particle being formed by nitride below particle diameter 500nm, the area occupation ratio of the precipitate of the nitrogenate the upper layer of the scope from above-mentioned surface to 10 μ m is 5～20%, therefore the hardness on surface has improved, even while use, also can relax the impression that generates while nipping impurity stress concentration around in the lubricating oil that is mixed with impurity.

Enlightened by these results, as the outer ring of embodiment 2-3, by forming carbonitrided case in non-grind section, in non-grind section, the generation of over cargurization tissue is suppressed.

On the other hand, from the result shown in table 18 and table 19, the outer ring of the comparative example 2-12 obtaining by the moulding starting material enforcement carburizing treatment to being obtained by steel C, on the surface of non-grind section nonnitrogenous (N).In addition, in the non-grind section of the outer ring of comparative example 2-12, have thick carbon compound particles more than particle diameter 10 μ m, therefore produced over cargurization tissue.

(test example 2-3)

Then, the outer inner ring of embodiment 2-3 and comparative example 2-8～2-12 has been carried out respectively to longevity test and compressive strength test in impurity oil.In the time carrying out in impurity oil longevity test, by the outer inner ring of embodiment 2-3 and the each example of comparative example 2-8～2-12 with by the ball combination of high-carbon-chromium bearing steel (JIS SUJ2) being implemented after carbonitriding is processed to quench again, temper is manufactured, assemble the spot contact bearing of model 6206, obtained spot contact bearing is offered to longevity test in impurity oil.In impurity oil, the test conditions of longevity test is the condition shown in above-mentioned table 2.The test conditions of compressive strength test is the condition shown in table 13.Compressive strength test is following test,, become the position of 180 ° to clamp along footpath direction at the second position with the first position of above-mentioned Zhou Fangxiang with being moved into along Zhou Fangxiang at the first position of the Zhou Fangxiang of 6206 outer rings with Amsler tester, make the first position and the second position speed with 0.5mm/min, along connecting the first position direction vertical with the axis with 6206 outer rings at the second position, move in the mode approaching, make thus above-mentioned 6206 race deformations and it is destroyed, then evaluate the radial loading while destruction.The ratio of the load of load when compressive strength rate is 6206 outer ring destroyed of each embodiment, comparative example during with respect to 6206 outer ring destroyed of comparative example 8.Then, these be the results are shown in to table 20.

[table 20]

	Life-span in impurity oil (L10)	Compressive strength rate
			Embodiment 2-3	8	1.0
Comparative example 2-8	1	1
			Comparative example 2-9	3.1	0.6
Comparative example 2-10	3.4	0.95
			Comparative example 2-11	1.3	1.1
Comparative example 2-12	8.6	0.5

Result is as shown in Table 20 known, possesses the spot contact bearing of the outer ring of the embodiment 2-3 of the steel C of the composition of use table 7, compared with possessing the spot contact bearing of outer ring of the comparative example 2-8～2-12 that uses steel D, life in impurity oil, and the ultimate compression strength of its outer ring is also high.

On the other hand, result is as shown in Table 20 known, possess the moulding starting material that the identical steel C of the steel by used with the outer ring of embodiment 2-3 is obtained and implemented the spot contact bearing of the outer ring of the comparative example 2-12 of carburizing treatment, compared with possessing the spot contact bearing of outer ring of the comparative example 2-8～2-10 that uses steel D, the ultimate compression strength of its outer ring reduces.On the other hand, known, possess by the moulding starting material enforcement carbonitriding to being obtained by steel C and process the spot contact bearing of the outer ring of the embodiment 2-3 obtaining, in impurity oil, the ultimate compression strength both sides of life-span and outer ring thereof have improved.

Like this, in comparative example 2-9,2-12, find, in the non-grind section that is present in the part except above-mentioned groove portion, have thick carbon compound particles more than particle diameter 10 μ m, produced the over cargurization tissues such as free carbide, this over cargurization tissue becomes the starting point of stress concentration, makes thus the ultimate compression strength of rolling bearing reduce.And, in embodiment 2-3, by the steel of regulation are implemented to carbonitriding processing under defined terms, although the groove portion at rolling bearing forms the few long lifetime tissue (carburized structure) of precipitate, but can not produce thick carbon compound particles more than particle diameter 10 μ m in non-grind section, being suppressed of the over cargurization tissues such as free carbide, the reduction of ultimate compression strength is suppressed, and can realize higher rolling fatigue life.

Therefore, enlightened by these results, as embodiment 2-3, implement carbonitriding according to the moulding starting material by being obtained by the steel C forming of table 7 and process the raceway member obtaining, can not form over cargurization tissue in non-grind section, can obtain life-span and all rolling bearings of excellence of ultimate compression strength in impurity oil.

Label declaration

1,11 inner rings

1a, 11a groove portion

2,21,61 outer rings

2a, 21a, 61a groove portion

10 spot contact bearing

Claims

1. a bearing component parts, the steel of the vanadium of and less than 0.5 quality % above by the chromium that contains 3.2～5.0 quality %, 0.05 quality % obtain, and have the surface of having carried out fine grinding processing, it is characterized in that,

Carbon content the upper layer of the scope from described surface to 10 μ m is 1.1～1.6 quality %,

Vickers' hardness apart from the dark position of described surperficial 50 μ m is 740～900,

Remained austenite content apart from the dark position of described surperficial 10 μ m is 20～55 volume %,

Nitrogen content the upper layer of the scope from described surface to 10 μ m is 0.1～1.0 quality %,

The upper layer of the scope from described surface to 10 μ m, the particle of particle diameter 0.2～2 μ m that at least there is the particle of particle diameter 0.2～2 μ m being formed by vanadium nitride and/or formed by vanadium carbonitride, and the area occupation ratio of the particle of the particle of particle diameter 0.2～2 μ m being made up of described vanadium nitride the upper layer of the scope from described surface to 10 μ m and/or particle diameter 0.2～2 μ m being made up of vanadium carbonitride is 1～10%.

2. bearing component parts as claimed in claim 1, wherein,

Described steel are the vanadium of the above and less than 0.5 quality % of silicon, the manganese of 0.05～0.7 quality %, the chromium of 3.2～5.0 quality %, the molybdenum of 0.1～1.0 quality %, the 0.05 quality % of the carbon that contains 0.7～0.9 quality %, 0.05～0.70 quality %, and remainder is iron and the inevitable steel of impurity.

3. bearing component parts as claimed in claim 1, wherein,

Described bearing component parts is the raceway member with the groove portion of having carried out fine grinding processing, the carbon that described steel contain 0.7～0.9 quality %,

The surface of the non-grind section of the part beyond being present in described groove portion is 0.7～1.0 quality % to the carbon content the upper layer of the scope of 10 μ m, and, be 700～800 apart from the Vickers' hardness of the dark position of this surface 50 μ m.

4. a manufacture method for bearing component parts, described bearing component parts is bearing component parts claimed in claim 1, it is characterized in that, comprising:

Finishing step, implement precision work by the intermediate raw material to after described temper, obtain following bearing component parts: in described bearing component parts, carbon content the upper layer of the scope from surface to 10 μ m is 1.1～1.6 quality %, Vickers' hardness apart from the dark position of surperficial 50 μ m is 740～900, remained austenite content apart from the dark position of surperficial 10 μ m is 20～55 volume %, nitrogen content the upper layer of the scope from surface to 10 μ m is 0.1～1.0 quality %, the particle of particle diameter 0.2～2 μ m that there is the particle of particle diameter 0.2～2 μ m being formed by vanadium nitride and/or formed by vanadium carbonitride the upper layer of the scope from surface to 10 μ m, and, the area occupation ratio of the particle of the particle of particle diameter 0.2～2 μ m being made up of described vanadium nitride the upper layer of the scope from surface to 10 μ m and/or particle diameter 0.2～2 μ m being made up of vanadium carbonitride is 1～10%.

5. a manufacture method for bearing component parts, described bearing component parts is bearing component parts claimed in claim 3, it is characterized in that, comprising:

Heat treatment step, described moulding starting material are implemented the thermal treatment that comprises carbonitriding processing and obtained intermediate raw material, and described carbonitriding is treated in carbon potential 0.9～1.3, ammonia concentration are the carbonitriding atmosphere of 2～5 volume % heats more than 4 hours processing by these moulding starting material at 850～900 ℃; And

Finishing step, the part of the described roller surface of formation by the intermediate raw material to after described thermal treatment is implemented fine grinding processing, form described groove portion, obtain following raceway member: in described raceway member, be more than 1.1 quality % and less than 1.6 quality % from the surface of described groove portion to the carbon content the upper layer of the scope of 10 μ m, Vickers' hardness apart from the dark position of this surface 50 μ m is 740～900, remained austenite content apart from the dark position of described surperficial 10 μ m is 20～55 volume %, nitrogen content the upper layer of the scope from described surface to 10 μ m is 0.1～1.0 quality %, the particle of particle diameter 0.2～2 μ m that there is the particle of particle diameter 0.2～2 μ m being formed by vanadium nitride and/or formed by vanadium carbonitride the upper layer of the scope from surface to 10 μ m, and, the area occupation ratio of the particle of the particle of particle diameter 0.2～2 μ m being made up of described vanadium nitride the upper layer of the scope from surface to 10 μ m and/or particle diameter 0.2～2 μ m being made up of vanadium carbonitride is 1～10%, the surface of the non-grind section of the part beyond being present in described groove portion is 0.7～1.0 quality % to the carbon content the upper layer of the scope of 10 μ m, and the Vickers' hardness apart from the dark position of this surface 50 μ m is 700～800.

6. a rolling bearing, have inner peripheral surface have the outer ring of groove portion, periphery have groove portion inner ring, be disposed at the multiple rolling bodys between two groove portion of described Internal and external cycle, it is characterized in that,

At least one party in described outer ring and inner ring is made up of the bearing component parts described in any one in claim 1～3.

7. a bearing component parts, the moulding starting material that process by the steel of the vanadium to the chromium that contains 3.2～5.0 quality %, 0.05 quality % is above and less than 0.5 quality %, after implementing carbonitriding processing, deepfreeze at again obtained intermediate raw material being implemented to-50～-100 ℃ and precision work and obtain, there is the surface of having carried out fine grinding processing, it is in the carbonitriding atmosphere of 2～5 volume % that described carbonitriding is treated at carbon potential 0.9～1.3, ammonia concentration, at 850～900 ℃, then heating carries out the processing of chilling, it is characterized in that

Be 1.1～1.6 quality % from the surface of having carried out described fine grinding processing to the carbon content the upper layer of the scope of 10 μ m, Vickers' hardness apart from the dark position of described surperficial 50 μ m is 800～940, remained austenite content apart from the dark position of described surperficial 10 μ m is 5～30 volume %, nitrogen content the upper layer of the scope from described surface to 10 μ m is 0.1～1.0 quality %, the particle of particle diameter 0.2～2 μ m that there is the particle of particle diameter 0.2～2 μ m being formed by vanadium nitride and/or formed by vanadium carbonitride the upper layer of the scope from described surface to 10 μ m, and, the area occupation ratio of the particle of the particle of the particle diameter being made up of vanadium nitride 0.2～2 μ m the upper layer of the scope from described surface to 10 μ m and/or particle diameter 0.2～2 μ m being made up of vanadium carbonitride is 1～10%.

8. bearing component parts as claimed in claim 7, wherein,

9. a rolling bearing, has: inner peripheral surface have the outer ring of groove portion, periphery have groove portion inner ring, be disposed at the multiple rolling bodys between two groove portion of described outer inner ring, it is characterized in that,

Described outer ring is fixed ring, and is made up of the bearing component parts described in claim 7 or 8.

10. rolling bearing as claimed in claim 9, wherein,

Described inner ring encloses for driving, and is as lower member,

, by the chromium that contains 3.2～5.0 quality %, the steel of the vanadium of the above and less than 0.5 quality % of 0.05 quality % obtain, carbon content the upper layer of the scope from surface to 10 μ m is 1.1～1.6 quality %, Vickers' hardness apart from the dark position of surperficial 50 μ m is 740～900, remained austenite content apart from the dark position of surperficial 10 μ m is 20～55 volume %, nitrogen content the upper layer of the scope from surface to 10 μ m is 0.1～1.0 quality %, the particle of particle diameter 0.2～2 μ m that there is the particle of particle diameter 0.2～2 μ m being formed by vanadium nitride and/or formed by vanadium carbonitride the upper layer of the scope from surface to 10 μ m, and, the area occupation ratio of the particle of the particle of particle diameter 0.2～2 μ m being made up of described vanadium nitride the upper layer of the scope from described surface to 10 μ m and/or particle diameter 0.2～2 μ m being made up of vanadium carbonitride is 1～10%.

The manufacture method of 11. 1 kinds of bearing component parts, is characterized in that, comprising:

Finishing step, implement precision work by the intermediate raw material to after described deepfreeze operation, obtain following bearing component parts: in described bearing component parts, Vickers' hardness apart from the dark position of surperficial 50 μ m is 800～940, remained austenite content apart from the dark position of surperficial 10 μ m is 5～30 volume %, nitrogen content the upper layer of the scope from described surface to 10 μ m is 0.1～1.0 quality %, the particle of particle diameter 0.2～2 μ m that there is the particle of particle diameter 0.2～2 μ m being formed by vanadium nitride and/or formed by vanadium carbonitride the upper layer of the scope from described surface to 10 μ m, and, the area occupation ratio of the particle of the particle of particle diameter 0.2～2 μ m being made up of described vanadium nitride the upper layer of the scope from described surface to 10 μ m and/or particle diameter 0.2～2 μ m being made up of vanadium carbonitride is 1～10%.

12. 1 kinds of manufacture method as the raceway member of bearing component parts, described bearing component parts is bearing component parts claimed in claim 8, it is characterized in that, comprising:

Finishing step, the part of the described roller surface of formation by the intermediate raw material to after described deepfreeze operation is implemented fine grinding processing, form described groove portion, obtain following raceway member: in described raceway member, be more than 1.1 quality % and less than 1.6 quality % from the surface of described groove portion to the carbon content the upper layer of the scope of 10 μ m, Vickers' hardness apart from the dark position of this surface 50 μ m is 800～940, remained austenite content apart from the dark position of described surperficial 10 μ m is 5～30 volume %, nitrogen content the upper layer of the scope from described surface to 10 μ m is 0.1～1.0 quality %, the particle of particle diameter 0.2～2 μ m that there is the particle of particle diameter 0.2～2 μ m being formed by vanadium nitride and/or formed by vanadium carbonitride the upper layer of the scope from surface to 10 μ m, and, the area occupation ratio of the particle of the particle of the particle diameter being made up of vanadium nitride 0.2～2 μ m the upper layer of the scope from surface to 10 μ m and/or particle diameter 0.2～2 μ m being made up of vanadium carbonitride is 1～10%, the surface of the non-grind section of the part beyond being present in described groove portion is 0.7～1.0 quality % to the carbon content the upper layer of the scope of 10 μ m, and the Vickers' hardness apart from the dark position of this surface 50 μ m is 700～800.